Mobile communication system, base station apparatus, mobile station apparatus, and communication method

ABSTRACT

A mobile station (MS) communicates with a base station (BS) by a carrier aggregation using a plurality of downlink component carriers (DCCs). The MS receives on one or more activated DCCs. The MS receives using a PDCCH on one of activated DCCs, from the BS, first information including an information field for requesting a transmission of channel state information (CSI), the first information being used for scheduling of a PUSCH. The MS transmits using the PUSCH in a first subframe on an uplink component carrier, to the BS, first CSI for more than one activated DCCs. The MS transmits using the PUSCH in a second subframe on the uplink component carrier, to the BS, second CSI for only one activated downlink component carrier. The transmission of the second CSI is scheduled by the first information received using the PDCCH on the only one activated downlink component carrier.

This application is a Continuation of U.S. application Ser. No.16/584,211, filed Sep. 26, 2019, which is a Continuation of U.S.application Ser. No. 15/959,231, filed Apr. 22, 2018, issued as U.S.Pat. No. 10,455,572 on Oct. 22, 2019, which is a Continuation of U.S.application Ser. No. 15/189,793, filed Jun. 22, 2016, issued as U.S.Pat. No. 9,955,471 on Apr. 24, 2018, which is a Continuation of U.S.application Ser. No. 14/641,048, filed on Mar. 6, 2015, issued as U.S.Pat. No. 9,398,582 on Jul. 19, 2016, which is a Continuation of U.S.application Ser. No. 13/635,760, filed on Oct. 31, 2012, issued as U.S.Pat. No. 9,008,021 on Apr. 14, 2015, which was filed as PCTInternational Application No. PCT/JP2011/056357 on Mar. 17, 2011, whichclaims the benefit under 35 U.S.C. § 119(a) to Patent Application No.2010-064169, filed in Japan on Mar. 19, 2010, all of which are herebyexpressly incorporated by reference into the present application intheir entirety.

TECHNICAL FIELD

The present invention relates to a mobile communication system, a basestation apparatus, a mobile station apparatus, and a communicationmethod.

BACKGROUND ART

In the 3rd Generation Partnership Project (3GPP), utilizing a radioaccess system and evolution of radio network of cellular mobilecommunication (referred to as “LongTerm Evolution (LTE)” or “EvolvedUniversal Terrestrial Radio Access (EUTRA)” in the following), and awider frequency band, a radio access system and radio network are underconsideration which realize faster data communication (referred to as“Long Term Evolution-Advanced (LTE-A, A-LTE)” or “Advanced EvolvedUniversal Terrestrial Radio Access (A-EUTRA)” in the following).

In LTE, as a downlink (radio communication from a base station apparatusto a mobile station apparatus), Orthogonal Frequency DivisionMultiplexing (OFDM) method is used, which is multi-carrier transmission.In addition, as an uplink (radio communication from a mobile stationapparatus to a base station apparatus), SC-FDMA (Single-CarrierFrequency-Division Multiple Access) method is used, which issingle-carrier transmission.

FIG. 18 illustrates a downlink radio frame structure in LTE. In thedownlink, a Physical Downlink Control Channel (PDCCH), a PhysicalDownlink Shared Channel (PDSCH), or the like are mapped. In addition, adownlink reference signal is mapped to a part of the PDSCH. In addition,a downlink radio frame includes a downlink Resource Block (RB) pair.

The downlink RB pair, which is a unit of RB used when assigning adownlink radio resource, includes a frequency band (RB bandwidth) with apredetermined width and a time zone (2 slots=1 subframe). A downlink RBpair includes two downlink RBs (RB bandwidth×slot) which are contiguousin the time domain.

For example, a downlink RB includes 12 subcarriers in the frequencydomain and includes seven OFDM symbols in the time domain. Here, a PDCCHis a physical channel which carries a mobile station identifier,scheduling information of a PDSCH, scheduling information of a PhysicalUplink Shared Channel (PUSCH), Modulation and Coding Scheme (MCS)information (modulation scheme and coding rate), retransmissionparameter information or the like, and which carries Downlink ControlInformation (DCI).

Here, a mobile station identifier, which is, for example, a C-RNTI(Cell-Radio Network Temporary Identifier), is an identifier effectiveonly within a cell managed by a base station apparatus. The C-RNTI isassigned to a mobile station apparatus by the base station apparatus. Inaddition, scheduling information of a PDSCH may include RB assignmentinformation for the PDSCH. In addition, scheduling information of aPUSCH may include RB assignment information for the PUSCH.

FIG. 19 illustrates an uplink radio frame structure in LTE. In theuplink, a Physical Uplink Control Channel (PUCCH), a Physical UplinkShared Channel (PUSCH), or the like are mapped. In addition, an uplinkreference signal is mapped to a part of the PUSCH and PUCCH. Inaddition, an uplink radio frame includes an uplink RB pair.

The uplink RB pair, which is a unit of RB used when assigning an uplinkradio resource, includes a frequency band (RB bandwidth) with apredetermined width and a time zone (2 slots=1 subframe). For example,an uplink RB pair includes two uplink RBs (RB bandwidth×slot) which arecontiguous in the time domain. In addition, for example, an uplink RBincludes 12 subcarriers in the frequency domain and includes 7 SC-FDMAsymbols in the time domain.

FIG. 20 is a schematic view illustrating reporting (feedback) of ChannelStatement information (CSI) in LTE. Here, the channel state informationincludes a Channel Quality indicator (CQI).

A base station apparatus 2001 notifies a mobile station apparatus 2002of DCI2003 including uplink scheduling information (RB assignmentinformation) indicating on which RB the mobile station apparatus 2002transmits an uplink transmission signal 2004 including the channel stateinformation. Based on the DCI notified from the base station apparatus2001, the mobile station apparatus 2002 transmits the uplinktransmission signal 2004 including the channel state information to thebase station apparatus 2001.

FIG. 21 illustrates an exemplary configuration of a Downlink ControlInformation Format (DCI format) in LTE. As described in Non-patentdocument 1, a plurality of bit fields (information fields) is defined ina DCI Format0 including uplink-related information such as uplinkscheduling information.

As illustrated in FIG. 21 , for example, the leading bit field of theDCI Format0 includes a flag (Flag for Format0/Format1A) fordistinguishing between the Format0 and Format1A which is anotherdownlink control information format. The mobile station apparatusrecognizes (identifies) the configuration of subsequent bit fields byfirst checking the flag for distinguishing between the Format0 andFormat1A.

In addition, the DCI Format0 includes (is formed by) a bit fieldindicating uplink scheduling such as Hopping flag, RB assignment(Resource Block assignment) information or the like, a bit field for MCS(Modulation and Coding Scheme) and RV (Redundancy Version) indicatingthe modulation scheme, coding rate, retransmission parameters or thelike, a bit field for New Data Indicator indicating whether thetransmission is an initial transmission or a re-transmission, a bitfield for CQI request indicating whether or not reporting of the channelstate information (the channel quality indicator) is requested (bitfield indicating whether or not a transmission of the channel stateinformation (the channel quality indicator) is instructed), or the like.

For example, when the CQI request field of the DCI Format0 transmittedfrom the base station apparatus indicates a state in which reporting ofthe channel state information is performed (e.g., when the CQI requestfield is set to “1”), the mobile station apparatus transmits an uplinktransmission signal including the channel state information to the basestation apparatus.

PRIOR ART DOCUMENT Non-Patent Document

-   Non-patent document 1: “3GPPTS36.212 v8.7.0 (2009-05)”, May, 2009.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, there has been a problem that, since the prior art assumes asystem in which the number of bands as measurement (generation) targetsof the channel state information between the base station apparatus andthe mobile station apparatus is one, in a system where two or more bandsthe channel state information of which is to be measured can beconfigured, it has been impossible to specify measurement target ofchannel state or transmission resource, which may result in a decreasedspectrum efficiency.

The present invention has been made in view of the above-mentionedproblem, and has an object to provide, in a system where two or morebands channel state information of which is to be measured can beconfigured, a mobile communication system, a base station apparatus, amobile station apparatus, and a communication method which can flexiblyconfigure measurement target of channel state or transmission resource.

Means for Solving the Problems

(1) In order to achieve the above-mentioned object, an embodiment of thepresent invention has taken the following measures. That is, a mobilecommunication system of the present invention is the one in which a basestation apparatus and a mobile station apparatus communicate with eachother using a plurality of component carriers configured by the basestation apparatus, wherein the base station apparatus notifies themobile station apparatus of a downlink control information format usedfor scheduling of a physical uplink shared channel in a certain specificuplink component carrier and, the mobile station apparatus, whendownlink control information included in the downlink controlinformation format is set to request transmission of channel stateinformation, transmits, to the base station apparatus, channel stateinformation of a downlink component carrier corresponding to the certainspecific uplink component carrier.

(2) In addition, the mobile communication system of an embodiment of thepresent invention is characterized in that the mobile station apparatustransmits the channel state information to the base station apparatus,using the physical uplink shared channel in the certain specific uplinkcomponent carrier.

(3) In addition, a mobile communication system of an embodiment of thepresent invention is the one in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by the base station apparatus, whereinthe base station apparatus notifies the mobile station apparatus of adownlink control information format used for scheduling of a physicaluplink shared channel and, the mobile station apparatus, when downlinkcontrol information included in the downlink control information formatis set to request transmission of channel state information, transmits,to the base station apparatus using the physical uplink shared channel,channel state information of a downlink component carrier in which thedownlink control information format has been detected.

(4) In addition, a mobile communication system of an embodiment of thepresent invention is the one in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by the base station apparatus, whereinthe base station apparatus notifies the mobile station apparatus of aphysical downlink control channel to which downlink control informationis mapped and, the mobile station apparatus, when the downlink controlinformation is set to request transmission of channel state information,transmits, to the base station apparatus, channel state information of adownlink component carrier determined according to a search space inwhich the physical downlink control channel has been detected.

(5) In addition, the mobile communication system of an embodiment of thepresent invention is characterized in that the mobile station apparatustransmits the channel state information to the base station apparatus,using a physical uplink shared channel which has been scheduledaccording to a downlink control information format including thedownlink control information.

(6) In addition, a mobile communication system of an embodiment of thepresent invention is the one in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by the base station apparatus, whereinthe base station apparatus notifies the mobile station apparatus of adownlink control information format used for scheduling of a physicaluplink shared channel in a certain specific uplink component carrierand, the mobile station apparatus, according to a request fortransmission of channel state information indicated by informationincluded in the downlink control information format and a downlinkcomponent carrier associated with channel state information, transmits,to the base station apparatus, channel state information of the downlinkcomponent carrier, using the physical uplink shared channel in thecertain specific uplink component carrier.

(7) In addition, the mobile communication system of an embodiment of thepresent invention is characterized in that the channel state informationincludes a channel quality indicator.

(8) In addition, a base station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a notifierwhich notifies the mobile station apparatus of a downlink controlinformation format used for scheduling of a physical uplink sharedchannel in a certain specific uplink component carrier; and a receiverwhich receives, from the mobile station apparatus, channel stateinformation of a downlink component carrier corresponding to the certainspecific uplink component carrier, when downlink control informationincluded in the downlink control information format has been set torequest transmission of channel state information.

(9) In addition, the base station apparatus of an embodiment of thepresent invention is characterized in that the receiver which receivesthe channel state information from the mobile station apparatus uses thephysical uplink shared channel in the certain specific uplink componentcarrier to receive the channel state information from the mobile stationapparatus.

(10) In addition, a base station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a notifierwhich notifies the mobile station apparatus of a downlink controlinformation format used for scheduling of a physical uplink sharedchannel; and a receiver which receives, from the mobile stationapparatus, channel state information of a downlink component carrier inwhich the mobile station apparatus has detected the downlink controlinformation format, using the physical uplink shared channel, whendownlink control information included in the downlink controlinformation format is set to request transmission of channel stateinformation.

(11) In addition, a base station apparatus of the an embodiment ofpresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a notifierwhich notifies the mobile station apparatus of a physical downlinkcontrol channel to which downlink control information is mapped; and areceiver which receives, from the mobile station apparatus, channelstate information of a downlink component carrier determined accordingto a search space in which the mobile station apparatus has detected thephysical downlink control channel, when the downlink control informationis set to request transmission of channel state information.

(12) In addition, the base station apparatus of an embodiment of thepresent invention is characterized in that the receiver which receivesthe channel state information from the mobile station apparatus uses aphysical uplink shared channel which has been scheduled according to adownlink control information format including the downlink controlinformation to receive the channel state information from the mobilestation apparatus.

(13) In addition, a base station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a notifierwhich notifies the mobile station apparatus of a downlink controlinformation format used for scheduling of a physical uplink sharedchannel in a certain specific uplink component carrier; and a receiverwhich receives, from the mobile station apparatus, channel stateinformation of the downlink component carrier, using the physical uplinkshared channel in the certain specific uplink component carrier,according to a request for transmission of channel state informationindicated by information included in the downlink control informationformat and a downlink component carrier associated with channel stateinformation.

(14) In addition, the base station apparatus of an embodiment of thepresent invention is characterized in that the channel state informationincludes a channel quality indicator.

(15) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: adetector which detects a downlink control information format used forscheduling of a physical uplink shared channel in a certain specificuplink component carrier; and a transmitter which transmits, to the basestation apparatus, channel state information of a downlink componentcarrier corresponding to the certain specific uplink component carrier,when downlink control information included in the downlink controlinformation format is set to request transmission of channel stateinformation.

(16) In addition, the mobile station apparatus of an embodiment of thepresent invention is characterized in that the transmitter whichtransmits the channel state information to the base station apparatususes the physical uplink shared channel in the certain specific uplinkcomponent carrier to transmit the channel state information to the basestation apparatus.

(17) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: adetector which detects a downlink control information format used forscheduling of a physical uplink shared channel; and a transmitter whichtransmits, to the base station apparatus, using the physical uplinkshared channel, channel state information of a downlink componentcarrier in which the downlink control information format has beendetected, when downlink control information included in the downlinkcontrol information format is set to request transmission of channelstate information.

(18) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: adetector which detects a physical downlink control channel to whichdownlink control information is mapped; and a transmitter whichtransmits, to the base station apparatus, channel state information of adownlink component carrier determined according to a search space inwhich the physical downlink control channel has been detected, when thedownlink control information is set to request transmission of channelstate information.

(19) In addition, the mobile station apparatus of an embodiment of thepresent invention is characterized in that the transmitter whichtransmits the channel state information to the base station apparatususes a physical uplink shared channel which has been scheduled accordingto a downlink control information format including the downlink controlinformation to transmit the channel state information to the basestation apparatus.

(20) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: adetector which detects a downlink control information format used forscheduling of a physical uplink shared channel in a certain specificuplink component carrier; and a transmitter which transmits, to the basestation apparatus, channel state information of the downlink componentcarrier, using the physical uplink shared channel in the certainspecific uplink component carrier, according to a request fortransmission of channel state information indicated by informationincluded in the downlink control information format and a downlinkcomponent carrier associated with channel state information.

(21) In addition, the mobile station apparatus of an embodiment of thepresent invention is characterized in that the channel state informationincludes a channel quality indicator.

(22) In addition, a communication method of an embodiment of the presentinvention is the one of a base station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: notifying the mobilestation apparatus of a downlink control information format used forscheduling of a physical uplink shared channel in a certain specificuplink component carrier; and receiving, from the mobile stationapparatus, channel state information of a downlink component carriercorresponding to the certain specific uplink component carrier, whendownlink control information included in the downlink controlinformation format is set to request transmission of channel stateinformation.

(23) In addition, the communication method of an embodiment of thepresent invention is characterized by including a step of receiving thechannel state information from the mobile station apparatus, using thephysical uplink shared channel in the certain specific uplink componentcarrier.

(24) In addition, a communication method of an embodiment of the presentinvention is the one of a base station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: notifying the mobilestation apparatus of a downlink control information format used forscheduling of a physical uplink shared channel; and receiving, from themobile station apparatus, using the physical uplink shared channel,channel state information of a downlink component carrier in which themobile station apparatus has detected the downlink control informationformat, when downlink control information included in the downlinkcontrol information format is set to request transmission of channelstate information.

(25) In addition, a communication method of an embodiment of the presentinvention is the one of a base station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: notifying the mobilestation apparatus of a physical downlink control channel to whichdownlink control information is mapped; and receiving, from the mobilestation apparatus, channel state information of a downlink componentcarrier determined according to a search space in which the mobilestation apparatus has detected the physical downlink control channel,when the downlink control information is set to request transmission ofchannel state information.

(26) In addition, the communication method of an embodiment of thepresent invention is characterized by including a step of receiving thechannel state information from the mobile station apparatus, using aphysical uplink shared channel which has been scheduled according to adownlink control information format including the downlink controlinformation.

(27) In addition, a communication method of an embodiment of the presentinvention is the one of a base station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: notifying the mobilestation apparatus of a downlink control information format used forscheduling of a physical uplink shared channel in a certain specificuplink component carrier; and receiving, from the mobile stationapparatus, channel state information of the downlink component carrier,using the physical uplink shared channel in the certain specific uplinkcomponent carrier, according to a request for transmission of channelstate information indicated by information included in the downlinkcontrol information format and a downlink component carrier associatedwith channel state information.

(28) In addition, the communication method of an embodiment of thepresent invention is characterized in that the channel state informationincludes a channel quality indicator.

(29) In addition, a communication method of an embodiment of the presentinvention is the one of a mobile station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: detecting a downlinkcontrol information format used for scheduling of a physical uplinkshared channel in a certain specific uplink component carrier; andtransmitting, to the base station apparatus, channel state informationof a downlink component carrier corresponding to the certain specificuplink component carrier, when downlink control information included inthe downlink control information format is set to request transmissionof channel state information.

(30) In addition, the communication method of an embodiment of thepresent invention is characterized by including a step of transmittingthe channel state information to the base station apparatus, using thephysical uplink shared channel in the certain specific uplink componentcarrier.

(31) In addition, a communication method of an embodiment of the presentinvention is the one of a mobile station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: detecting a downlinkcontrol information format used for scheduling of a physical uplinkshared channel; and transmitting, to the base station apparatus, usingthe physical uplink shared channel, channel state information of adownlink component carrier in which the downlink control informationformat has been detected, when downlink control information included inthe downlink control information format is set to request transmissionof channel state information.

(32) In addition, a communication method of an embodiment of the presentinvention is the one of a mobile station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: detecting a physicaldownlink control channel to which downlink control information ismapped; and transmitting, to the base station apparatus, channel stateinformation of a downlink component carrier determined according to asearch space in which the physical downlink control channel has beendetected, when the downlink control information is set to requesttransmission of channel state information.

(33) In addition, the communication method of an embodiment of thepresent invention is characterized by including a step transmitting thechannel state information to the base station apparatus, using aphysical uplink shared channel which has been scheduled according to adownlink control information format including the downlink controlinformation.

(34) In addition, a communication method of an embodiment of the presentinvention is the one of a mobile station apparatus in a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by the base station apparatus, thecommunication method including the steps of: detecting a downlinkcontrol information format used for scheduling of a physical uplinkshared channel in a certain specific uplink component carrier; andtransmitting, to the base station apparatus, channel state informationof the downlink component carrier, using the physical uplink sharedchannel in the certain specific uplink component carrier, according to arequest for transmission of channel state information indicated byinformation included in the downlink control information format and adownlink component carrier associated with channel state information.

(35) Additionally, the communication method of an embodiment of thepresent invention is characterized in that the channel state informationincludes a channel quality indicator.

(36) In addition, a base station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a basestation side transmitting unit which notifies the mobile stationapparatus of a downlink control information format used for schedulingof a physical uplink shared channel in a certain specific uplinkcomponent carrier; and a base station side receiving unit whichreceives, from the mobile station apparatus, channel state informationof a downlink component carrier corresponding to the certain specificuplink component carrier, when downlink control information included inthe downlink control information format is set to request transmissionof channel state information.

(37) In addition, the base station apparatus of an embodiment of thepresent invention is characterized in that the base station sidereceiving unit which receives the channel state information from themobile station apparatus uses the physical uplink shared channel in thecertain specific uplink component carrier to receive the channel stateinformation from the mobile station apparatus.

(38) In addition, a base station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a basestation side transmitting unit which notifies the mobile stationapparatus of a downlink control information format used for schedulingof a physical uplink shared channel; and a base station side receivingunit which receives, from the mobile station apparatus, using thephysical uplink shared channel, channel state information of a downlinkcomponent carrier in which the mobile station apparatus has detected thedownlink control information format, when downlink control informationincluded in the downlink control information format is set to requesttransmission of channel state information.

(39) In addition, a base station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a basestation side transmitting unit which notifies the mobile stationapparatus of a physical downlink control channel to which downlinkcontrol information is mapped; and a base station side receiving unitwhich receives, from the mobile station apparatus, channel stateinformation of a downlink component carrier determined according to asearch space in which the mobile station apparatus has detected thephysical downlink control channel, when the downlink control informationis set to request transmission of channel state information.

(40) In addition, the base station apparatus of an embodiment of thepresent invention is characterized in that the base station sidereceiving unit which receives the channel state information from themobile station apparatus uses a physical uplink shared channel which hasbeen scheduled according to a downlink control information formatincluding the downlink control information to receive the channel stateinformation from the mobile station apparatus.

(41) In addition, a base station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the base station apparatus including: a basestation side transmitting unit which notifies the mobile stationapparatus of a downlink control information format used for schedulingof a physical uplink shared channel in a certain specific uplinkcomponent carrier; and a base station side receiving unit whichreceives, from the mobile station apparatus, channel state informationof the downlink component carrier, using the physical uplink sharedchannel in the certain specific uplink component carrier, according to arequest for transmission of channel state information indicated byinformation included in the downlink control information format and adownlink component carrier associated with channel state information.

(42) In addition, the base station apparatus of an embodiment of thepresent invention is characterized in that the channel state informationincludes a channel quality indicator.

(43) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: a mobilestation side receiving unit which detects a downlink control informationformat used for scheduling of a physical uplink shared channel in acertain specific uplink component carrier; and a mobile station sidetransmitting unit which transmits, to the base station apparatus,channel state information of a downlink component carrier correspondingto the certain specific uplink component carrier, when downlink controlinformation included in the downlink control information format is setto request transmission of channel state information.

(44) In addition, the mobile station apparatus of an embodiment of thepresent invention is characterized in that the mobile station sidetransmitting unit which transmits the channel state information to thebase station apparatus uses the physical uplink shared channel in thecertain specific uplink component carrier to transmit the channel stateinformation to the base station apparatus.

(45) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: a mobilestation side receiving unit which detects a downlink control informationformat used for scheduling of a physical uplink shared channel; and amobile station side transmitting unit which transmits, to the basestation apparatus, using the physical uplink shared channel, channelstate information of a downlink component carrier in which the downlinkcontrol information format has been detected, when downlink controlinformation included in the downlink control information format is setto request transmission of channel state information.

(46) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: a mobilestation side receiving unit which detects a physical downlink controlchannel to which downlink control information is mapped; and a mobilestation side transmitting unit which transmits, to the base stationapparatus, channel state information of a downlink component carrierdetermined according to a search space in which the physical downlinkcontrol channel has been detected, when the downlink control informationis set to request transmission of channel state information.

(47) In addition, the mobile station apparatus of an embodiment of thepresent invention is characterized in that the mobile station sidetransmitting unit which transmits the channel state information to thebase station apparatus uses a physical uplink shared channel which hasbeen scheduled according to a downlink control information formatincluding the downlink control information to transmit the channel stateinformation to the base station apparatus.

(48) In addition, a mobile station apparatus of an embodiment of thepresent invention is the one in a mobile communication system in which abase station apparatus and a mobile station apparatus communicate witheach other using a plurality of component carriers configured by thebase station apparatus, the mobile station apparatus including: a mobilestation side receiving unit which detects a downlink control informationformat used for scheduling of a physical uplink shared channel in acertain specific uplink component carrier; and a mobile station sidetransmitting unit which transmits, to the base station apparatus,channel state information of the downlink component carrier, using thephysical uplink shared channel in the certain specific uplink componentcarrier, according to a request for transmission of channel stateinformation indicated by information included in the downlink controlinformation format and a downlink component carrier associated withchannel state information.

(49) In addition, the mobile station apparatus of an embodiment of thepresent invention is characterized in that the channel state informationincludes a channel quality indicator.

According to the present invention, measurement target of channel stateor a transmission resource can be flexibly specified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates simple overview of a radio communication systemaccording to an embodiment of the present invention;

FIG. 2 illustrates an exemplary structure of a downlink radio frameaccording to an embodiment of the present invention;

FIG. 3 illustrates an exemplary structure of an uplink radio frameaccording to an embodiment of the present invention;

FIG. 4 illustrates an exemplary configuration of downlink controlinformation format according to an embodiment of the present invention;

FIG. 5 illustrates another exemplary configuration of downlink controlinformation format according to an embodiment of the present invention;

FIG. 6 illustrates an exemplary specification of a downlink componentcarrier according to an embodiment of the present invention;

FIG. 7 illustrates an exemplary reporting procedure of channel stateinformation according to an embodiment of the present invention;

FIG. 8 illustrates an exemplary structure of a physical downlink controlchannel according to an embodiment of the present invention;

FIG. 9 illustrates another exemplary specification of a downlinkcomponent carrier according to an embodiment of the present invention;

FIG. 10 illustrates another exemplary structure of a physical downlinkcontrol channel according to an embodiment of the present invention;

FIG. 11 illustrates an exemplary pair of a downlink component carrierand an uplink component carrier according to an embodiment of thepresent invention;

FIG. 12 illustrates another exemplary reporting procedure of channelstate information according to an embodiment of the present invention;

FIG. 13 illustrates another exemplary reporting procedure of channelstate information according to an embodiment of the present invention;

FIG. 14 illustrates another exemplary configuration of downlink controlinformation format according to an embodiment of the present invention;

FIG. 15 illustrates a relation between a search space and a downlinkcontrol information format according to an embodiment of the presentinvention;

FIG. 16 illustrates an exemplary block configuration of a base stationapparatus 101 according to an embodiment of the present invention;

FIG. 17 illustrates an exemplary block configuration of a mobile stationapparatus 102 according to an embodiment of the present invention;

FIG. 18 illustrates an exemplary structure of a downlink radio frame inprior art;

FIG. 19 illustrates an exemplary structure of an uplink radio frame inprior art;

FIG. 20 illustrates an exemplary report of channel state information inprior art; and

FIG. 21 illustrates an exemplary configuration of downlink controlinformation format in prior art.

BEST MODES FOR CARRYING OUT THE INVENTION First Embodiment

In the following, a first embodiment of the present invention will bedescribed, referring to the drawings.

FIG. 1 is a schematic view of a radio communication system according tothe first embodiment. A base station apparatus (also referred to aseNodeB, eNB, downlink transmitting device, uplink receiving device, orcell) 101 performs radio communication with a mobile station apparatus(also referred to as UE: User Equipment, downlink receiving device,uplink transmitting device, or terminal) 102, using as least a pluralityof downlink component carriers and/or uplink component carriers (one ormore downlink component carriers and/or one or more uplink componentcarriers). Here, the downlink component carriers and/or the uplinkcomponent carriers on which the base station apparatus 101 and themobile station apparatus 102 perform communication with each other areconfigured by the base station apparatus 101 for the mobile stationapparatus 102.

Here, a Component Carrier (CC) indicates a (narrow) frequency band usedcompositely when the base station apparatus 101 and the mobile stationapparatus 102 perform communication with each other in a wider frequencyband. Hereinafter, in the present embodiment, a downlink componentcarrier is also referred to as a DLCC, and an uplink component carrieris also referred to as a ULCC. The base station apparatus 101 and themobile station apparatus 102 perform radio communication with each otherby forming a wider frequency band by aggregating one or more componentcarriers and using the component carriers compositely (referred to asCarrier Aggregation). For example, the base station apparatus 101 andthe mobile station apparatus 102 can realize higher speed radiocommunication by aggregating five component carriers each having abandwidth of 20 MHz to form a wider frequency band having a bandwidth of100 MHz and using these five frequency bands compositely.

In the present embodiment described below, a frequency band is definedby a bandwidth (Hz) or the number of resource blocks (RB) includingfrequency and time. In other words, a bandwidth may be defined by thenumber of resource blocks. In addition, a bandwidth and the number ofresource blocks can be defined also by the number of subcarriers.

A component carrier in the present embodiment indicates each (narrow)frequency band (e.g., a frequency band having a bandwidth of 20 MHz)constituting a (wider) frequency band (e.g., a frequency band having abandwidth of 100 MHz). In addition, a component carrier may indicate a(center) carrier frequency of each of the (narrow) frequency bands. Inaddition, a component carrier may be defined as a unit for forming aspecific physical channel (e.g., PDCCH, PUCCH, etc.).

Furthermore, a component carrier may be mapped in contiguous frequencybands or may be mapped in non-contiguous frequency bands. The basestation apparatus 101 and the mobile station apparatus 102 can performradio communication by aggregating component carriers which arecontiguous and/or non-contiguous frequency bands to form a widerfrequency band, and using these component carriers compositely.

Furthermore, the frequency band used for downlink communication and thefrequency band used for uplink communication formed by componentcarriers need not have a same bandwidth, and thus the base stationapparatus 101 and the mobile station apparatus 102 can performcommunication using compositely a downlink frequency band and an uplinkfrequency band having different bandwidths and formed by the componentcarrier (referred to as Asymmetric Carrier Aggregation). On the otherhand, performing communication between the base station apparatus 101and the mobile station apparatus 102 using compositely a downlinkfrequency band and an uplink frequency band having a same bandwidthformed by the component carrier is also referred to as Symmetric CarrierAggregation.

In FIG. 1 , when receiving an uplink transmission signal 104 from themobile station apparatus 102, the base station apparatus 101 notifiesthe mobile station apparatus 102 of Downlink Control Information (DCI)103 including uplink scheduling information indicating on which RB themobile station apparatus 102 transmits an uplink transmission signal(SC-FDMA signal or Clustered DFT (Discrete FourierTransformation)-precoded-OFDM signal), or information indicating whetheror not reporting of the channel state information is requested.

When the information transmitted from the base station apparatus 101 andindicating whether or not reporting of the channel state information isrequested indicates that reporting of the channel state information isrequested (e.g., when the CQI request field is set to “1”), the mobilestation apparatus 102 includes the channel state information in theuplink transmission signal 104 to be transmitted via a transmissionresource specified by the uplink scheduling information.

In the following, for simplicity, a case where information indicatingwhether or not reporting of the channel state information included inthe DCI from the base station apparatus 101 is requested indicates thatreporting of the channel state information is requested is alsodescribed as the CQI request field being set to “1”. Here, although thecase where reporting of the channel state information is requested isdescribed as a case where the CQI request field indicates “1”, it isneedless to say that the present embodiment can be applied regardless ofhow the base station apparatus 101 indicates request for reporting ofthe channel state information.

In addition, if there is no uplink data to be multiplexed in the uplinktransmission signal 104, or if transmission of only the controlinformation such as the channel state information is indicated by thedownlink control information 103, the mobile station apparatus 102transmits the uplink transmission signal 104 including only the controlinformation such as the channel state information. Here, uplink dataincludes a transport block for an Uplink-Shared Channel (UL-SCH). Theuplink shared channel is a transport channel and, if transmission ofonly the control information is instructed by the base station apparatus101, the mobile station apparatus 102 transmits the uplink transmissionsignal 104 including only the control information such as the channelstate information without any transport block for the UL-SCH accompaniedtherewith.

For example, upon receiving a request for reporting of the channel stateinformation from the base station apparatus 101, the mobile stationapparatus 102 transmits the uplink transmission signal 104 having thechannel state information and uplink data (UL-SCH) multiplexed(included) therein to the base station apparatus 101. In addition, forexample, when instructed to transmit only the control information by thebase station apparatus 101, the mobile station apparatus 102 transmitsthe uplink transmission signal 104 having only the channel stateinformation included therein without accompanying the uplink data(UL-SCH) to the base station apparatus 101.

FIG. 2 illustrates an exemplary structure of a downlink radio frameaccording to the present embodiment. A downlink has mapped therein aPhysical Downlink Control Channel (PDCCH), a Physical Downlink SharedChannel (PDSCH), or the like. In addition, a downlink reference signalis mapped to a part of the PDSCH.

In addition, a downlink radio frame includes a downlink Resource Block(RB) pair. The downlink RB pair, which is a unit of RB used whenassigning a downlink radio resource, includes a frequency band (RBbandwidth) and a time zone (2 slots=1 subframe) of a predeterminedwidth. A downlink RB pair includes two contiguous downlink RBs (RBbandwidth×slot) in the time domain. For example, a downlink RB includes12 subcarriers in the frequency domain and 7 OFDM symbols in the timedomain.

Here, a PDCCH is a region to which downlink control information (DCI) ismapped. In addition, a downlink subframe has subframes DLCC-0 to DLCC-Mwhich are M Downlink Component Carriers (DLCC) each having apredetermined bandwidth.

FIG. 3 illustrates an exemplary structure of an uplink radio frameaccording to the present embodiment. In the uplink a Physical UplinkShared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH), andthe like are assigned. In addition, an uplink reference signal isassigned to a part of the PUSCH or the PUCCH.

In addition, an uplink radio frame includes an uplink Resource Block(RB) pair. The uplink RB pair, which is a unit of RB used when assigningan uplink radio resource, includes a frequency band (RB bandwidth) and atime zone (2 slots=1 subframe) of a predetermined width. An uplink RBpair includes two contiguous uplink RBs (RB bandwidth×slot) in the timedomain. For example, an uplink RB includes 12 subcarriers in thefrequency domain and 7 SC-FDMA symbols or Clustered DFT-precoded-OFDMsymbols in the time domain.

In addition, there are subframes ULCC-0 to ULCC-N, as uplink subframes,which are N Uplink Component Carriers (ULCC) each having a predeterminedbandwidth. As described above, M, the number of DLCCs, and N, the numberof ULCCs, may take a same value or may take different values.

FIG. 4 illustrates an exemplary configuration of downlink controlinformation format (DCI Format) according to the first embodiment. FIG.4 illustrates two examples as a downlink control information format (DCIFormat0) to be used in the uplink. As shown in FIG. 4 , the two Format0srespectively include uplink-related information such as uplinkscheduling information and respectively have a plurality of bit fields(information fields) (formed by bit fields).

The DCI Format0 illustrated on the left side of FIG. 4 is used when, forexample, the base station apparatus 101 communicates with the mobilestation apparatus 102 using a ULCC which is configured by the basestation apparatus 101 to be Cell-specific or UE-specific. Is is alsoused when, for example, the base station apparatus 101 communicates withthe mobile station apparatus 102 using a fixed ULCC. It is also usedwhen, for example, the base station apparatus 101 communicates with themobile station apparatus 102 using a single ULCC. In other words, theDCI Format0 illustrated on the left side of FIG. 4 may be used whenthere is a common recognition between the base station apparatus 101 andthe mobile station apparatus 102 as to in which ULCC the relatedinformation is included (for example, as to resource assignmentinformation for the PUSCH allocated to which ULCC).

For example, the leading bit field of the DCI Format0 illustrated on theleft side of FIG. 4 includes a flag (Flag for Format0/Format1A) fordistinguishing between the DCI Format0 and Format1A which is anotherdownlink control information format. The mobile station apparatus 102first checks the flag for distinguishing between the DCI Format0 andFormat1A, and recognizes (identifies) subsequent bit fieldconfigurations.

In addition, the DCI Format0 includes (is formed by) a bit fieldindicating uplink scheduling such as a Hopping flag, RB assignmentinformation or the like; a bit field for an MCS (Modulation and CodingScheme) and RV (Redundancy Version) indicating modulation scheme andcoding rate, parameters for retransmission or the like; a bit field forNew Data Indicator indicating whether the transmission is initialtransmission or re-transmission; a bit field for CQI request indicatingwhether or not reporting of the channel state information (the channelquality indicator) is requested (bit field indicating an instruction totransmit the channel state information), or the like.

Here, the mobile station apparatus 102 recognizes, in common with thebase station apparatus 101, which ULCC the uplink RB assigned based onthe hopping flag and the RB assignment information is associated with.For example, when the CQI request field included in the DCI Format0indicates a state to report the channel state information, the mobilestation apparatus 102 generates channel state information and reportsthe generated channel state information via the PUSCH assigned by theDCI Format0.

As described above, the base station apparatus 101 can configure, forthe mobile station apparatus 102, the ULCC to be Cell-specific ormobile-station-apparatus-specific (UE-specific). In other words, thebase station apparatus 101 can preliminarily configure the ULCC for themobile station apparatus 102. In addition, the base station apparatus101 may configure, for the mobile station apparatus 102, thecorrespondence (linking) between the DLCC and the ULCC to beCell-specific or UE-specific. In other words, the base station apparatus101 can preliminarily configure the link between the DLCC and the ULCCfor the mobile station apparatus 102. Here, the DCI Format0 illustratedon the left side of FIG. 4 can be regarded as a DCI Format0 notincluding a CIF (Carrier Indicator Field) described below.

For example, when a PUSCH is assigned by the DCI Format0 not including aCIF, the mobile station apparatus 102 reports the channel stateinformation via a PUSCH allocated in a ULCC configured by the basestation apparatus 101.

In addition, when a PUSCH is assigned by a DCI Format0 not including aCIF allocated in a certain DLCC (e.g., DLCC-1), for example, the mobilestation apparatus 102 reports the channel state information via a PUSCHallocated in a ULCC (e.g., UL-CC2) linked to a certain DLCC by the basestation apparatus 101. Here, it is assumed that the base stationapparatus 101 has linked the DLCC-1 and the ULCC-2 to the mobile stationapparatus 102 in a Cell-specific or UE-specific manner.

The DCI Format0 illustrated on the right side of FIG. 4 includes, inaddition to the DCI Format0 illustrated on the left side of FIG. 4 , abit field for a CIF (Carrier Indicator Field). Here, the CIF is a fieldfor a Carrier Indicator indicating which ULCC the uplink RB assigned bythe hopping flag and the RB assignment information is associated with.For example, using the CIF, the base station apparatus 101 can indicate,to the mobile station apparatus 102, a ULCC to which a PUSCH assigned bythe DCI Format0 is allocated.

The mobile station apparatus 102 transmits the PUSCH using the uplink RBassigned by the hopping flag and the RB assignment information in theULCC indicated by the CIF. Here, if the CQI request field included inthe DCI Format0 from the base station apparatus 101 is set to “1”, themobile station apparatus 102 generates the channel state information andreports the generated channel state information via the PUSCH assignedby the DCI Format0 including the CIF.

Here, 0-padding (region shown by diagonal lines) at the end of the twoFormat0s shown in FIG. 4 is inserted in order to equalize the payloadsize (number of bits) of the Format0 and Format1A (indicating a bitfield with value 0, for example). For example, the 0-padding may beinserted when the number of bits of the Format0 is smaller than thenumber of bits of the Format1A.

FIG. 5 illustrates another exemplary configuration of downlink controlinformation format (DCI Format) according to the first embodiment. Thetwo DCI Format0s shown in FIG. 5 include, in addition to the DCI Format0shown in FIG. 4 , a Carrier Indicator Field for the channel stateinformation (Carrier Indicator for the CSI). Here, the CIF for thechannel state information may be a CIF for the CQI (Carrier Indicatorfor the CQI). In FIG. 5 , for clarity, the Carrier Indicator shown inFIG. 4 is described as a Carrier Indicator for the PUSCH.

Here, if the CQI request field included in the DCI Format0 from the basestation apparatus 101 is set to “1”, the CIF for the CSI is a field forCarrier Information indicating which DLCC the channel state informationis associated with.

When acquisition of the channel state information in any DLCC isdesired, the base station apparatus 101 specifies a state to report thechannel state information in the CQI request field, and also indicates,in the CIF for the CSI, the DLCC for which acquisition of the channelstate information is desired to the mobile station apparatus 102. Themobile station apparatus 102 generates the channel state information forthe DLCC indicated by the CIF for the CSI which has been transmittedfrom the base station apparatus 101, and reports the generated channelstate information via the PUSCH assigned by the DCI Format0.

In other words, the mobile station apparatus 102 generates (measures)the channel state information for the DLCC indicated by the CIF for theCSI included in the DCI Format0. In addition, the mobile stationapparatus 102 reports the generated channel state information to thebase station apparatus 101 via the PUSCH assigned by the DCI Format0.

Here, whether or not a CIF is included in the DCI Format watched(monitored) by the mobile station apparatus 102 may be set using an RRC(Radio Resource Control) reconfiguration procedure from the base stationapparatus 101. Upon receiving a message (RRC reconfiguration message)indicating to change the type of the monitored DCI Format and themeaning of each field of the monitored DCI Format, the mobile stationapparatus 102 transmits, to the base station apparatus 101, a message(RRC reconfiguration completion message) indicating that the type of themonitored DCI Format and the meaning of each field of the monitored DCIFormat have been changed.

As shown in the foregoing, it is possible to flexibly specify measuringtarget of the channel state information in a system where two or morebands (e.g., component carriers) can be configured which are measuring(generating) targets of the channel state information by transmitting,from the base station apparatus 101 to the mobile station apparatus 102,a DCI Format0 including a bit field for indicating whether or notreporting of the channel state information is requested, together withan additional bit field (the CIF for the CSI) indicating which componentcarrier the channel state information is associated with.

The mobile station apparatus 102 may generate (measure) the channelstate information for a DLCC indicated by the CIF for the channel stateinformation included in the DCI Format, and whereby the base stationapparatus 101 can flexibly specify, for the mobile station apparatus102, a DLCC for generating the channel state information.

In addition, if the PUSCH is assigned by the DCI Format0 not includingthe CIF field, the mobile station apparatus 102 may report the channelstate information via the PUSCH allocated on the ULCC which has been(preliminarily) configured by the base station apparatus 101, andwhereby the base station apparatus 101 can flexibly configure (assign) atransmission resource by which the mobile station apparatus 102 reportsthe channel state information.

In addition, if the PUSCH is assigned by the DCI Format0 not includingthe CIF field mapped on a certain DLCC, the mobile station apparatus 102may report the channel state information via a PUSCH allocated on a ULCCwhich has been (preliminarily) linked to the certain DLCC by the basestation apparatus 101, and whereby the base station apparatus 101 canflexibly configure (assign) a transmission resource by which the mobilestation apparatus 102 reports channel state information.

In addition, if the PUSCH is assigned by the DCI Format0 including theCIF field, the mobile station apparatus 102 may report the channel stateinformation via a PUSCH allocated on a ULCC indicated by the CIF, andwhereby the base station apparatus 101 can quickly configure (assign) atransmission resource by which the mobile station apparatus 102transmits channel state information.

Second Embodiment

Next, a second embodiment of the present invention will be described. Inthe first embodiment of the present invention, description has beenprovided such that the base station apparatus 101 transmits the DCIFormat0 including a bit field for indicating whether or not reporting ofthe channel state information is requested, together with a bit field(information) included therein, instructing for which DLCC the mobilestation apparatus 102 is supposed to generate (measure) the channelstate information, and the mobile station apparatus 102 generates thechannel state information for the DLCC instructed by the base stationapparatus 101 and reports the generated channel state information.

Description will be provided for the second embodiment of the presentinvention such that the base station apparatus 101 instructs for whichDLCC the mobile station apparatus 102 is supposed to generate thechannel state information, depending on which region (which a DLCC, orwhich a SS: a search space) the DCI (or may be the DCI Format0) issupposed to be allocated in. For example, the base station apparatus 101can instruct for which DLCC the mobile station apparatus 102 is supposedto generate the channel state information, based on the DLCC on whichDCI (or may be the DCI Format0) transmitted. In other words, a DLCC forwhich the mobile station apparatus 102 generates the channel stateinformation can be implicitly specified by the DLCC on which the basestation apparatus 101 transmitted the DCI.

In other words, the mobile station apparatus 102 determines (identifies)for which DLCC the channel state information is supposed to begenerated, based on the DLCC on which the DCI (or may be the DCIFormat0) addressed to its own apparatus has been detected, generates thechannel state information for one of the DLCCs, and reports thegenerated channel state information to the base station apparatus 101.In other words, the mobile station apparatus 102 attempts to detect DCIaddressed to its own apparatus which has been allocated on the DLCC(performs blind decoding), generates the channel state information for aDLCC corresponding to the DLCC on which the DCI addressed to its ownapparatus has been detected, and reports the generated channel stateinformation to the base station apparatus 101.

In addition, for example, the base station apparatus 101 can instructfor which DLCC the mobile station apparatus 102 is supposed to generatethe channel state information, based on a Search Space (SS, alsoreferred to as a search region) on which DCI (or may be the DCI Format0)is transmitted. In other words, the mobile station apparatus 102 candetermine (identify) for which DLCC the channel state information issupposed to be generated, based on the search space on which the DCI (ormay be the DCI Format0) addressed to its own apparatus has beendetected, generate the channel state information for one of the DLCCs,and transmit the generated channel state information to the base stationapparatus 101.

A radio communication system according to the second embodiment can beimplemented by a configuration similar to that of the radiocommunication system shown in FIG. 1 . First, a case of instructing forwhich DLCC the mobile station apparatus 102 is supposed to generate thechannel state information, based on the DLCC on which the base stationapparatus 101 transmits DCI will be described.

FIG. 6 illustrates an exemplary specification of a DLCC based onallocation of DCI according to the second embodiment. FIG. 6 illustratesan example in which, for example, when the base station apparatus 101communicates with the mobile station apparatus 102 using three DLCCs(e.g., DLCC-0, DLCC-1, and DLCC-2) and two ULCCs (e.g., ULCC-0 andULCC-1), the base station apparatus 101 specifies, to the mobile stationapparatus 102, a DLCC for generating channel state information.

The DLCC illustrated on the left side of FIG. 6 indicates a DLCC (or maybe a DLCC on which the mobile station apparatus 102 detects DCIaddressed to its own apparatus) on which the base station apparatus 101transmits DCI, and CQI reference resources illustrated on the right sideof FIG. 6 indicate a DLCC for the mobile station apparatus 102 togenerate the channel state information corresponding to the DLCC (or maybe the DLCC on which the mobile station apparatus 102 detects DCIaddressed to its own apparatus) on which the base station apparatus 101transmits DCI. In other words, if the CQI request field included in theDCI Format0 from the base station apparatus 101 is set to “1”, acorrespondence (correspondence table, linking) is shown, instructing forwhich DLCC the mobile station apparatus 102 is supposed to generate thechannel state information.

For example, as shown in FIG. 6 , upon detecting the DCI addressed toits own apparatus which has been transmitted on the DLCC-0, and if theCOI request field in the DCI is set to “1” by the base station apparatus101, the mobile station apparatus 102 generates the channel stateinformation for the DLCC-0, and reports the generated channel stateinformation. In addition, for example, upon detecting the DCI addressedto its own apparatus which has been transmitted on the DLCC-1, and ifthe CQI request field in the DCI is set to “I” by the base stationapparatus 101, the mobile station apparatus 102 generates the channelstate information for the DLCC-2 and reports the generated channel stateinformation. In addition, for example, upon detecting the DCI addressedto its own apparatus which has been transmitted on the DLCC-2, and ifthe CQI request field in the DCI is set to “1” by the base stationapparatus 101, the mobile station apparatus 102 generates the channelstate information for the DLCC-1 and reports the generated channel stateinformation.

Here, the mobile station apparatus 102, after having checked the DLCCwith DCI transmitted therein, may generate the channel state informationfor the DLCC with DCI transmitted therein, and report the generatedchannel state information. In addition, after having preliminarilygenerated the channel state information for a plurality of DLCCs andchecked the DLCC with DCI transmitted therein, the mobile stationapparatus 102 may report the channel state information corresponding tothe DLCC with DCI allocated therein.

In addition, the correspondence (correspondence table, linking) betweenthe DLCC on which the base station apparatus 101 transmits DCI and theDLCC for the mobile station apparatus 102 to generate the channel stateinformation may be set by the base station apparatus 101 to beCell-specific or UE-specific. In other words, the base station apparatus101 and the mobile station apparatus 102 are caused to share thecorrespondence before the DCI Format0 is transmitted from the basestation apparatus 101.

In addition, correspondence (correspondence table, linking) between theDLCC on which the base station apparatus 101 transmits DCI and the DLCCfor the mobile station apparatus 102 to generate the channel stateinformation may be set by the base station apparatus 101 in asemi-static or a dynamic manner. In addition, the DLCC on which the basestation apparatus 101 transmits DCI and the DLCC for the mobile stationapparatus 102 to generate the channel state information need not beidentical. Even if the DLCC on which the base station apparatus 101transmits DCI is not identical to the DLCC for the mobile stationapparatus 102 to generate the channel state information, a similareffect can be obtained.

FIG. 7 illustrates an exemplary reporting procedure of the channel stateinformation according to the second embodiment. First, the base stationapparatus 101 notifies the mobile station apparatus 102 of DCI includinguplink-related information via a DLCC corresponding to the DLCC forwhich acquisition of the channel state information is desired. In otherwords, the base station apparatus 101 transmits DCI (DCI Format0) on aDLCC corresponding to the DLCC for which acquisition of the channelstate information is desired, and transmits it to the mobile stationapparatus 102. In addition, the base station apparatus 101 specifies astate to report the channel state information in the CQI request fieldincluded in the DCI (sets the CQI request field to “1”).

In FIG. 7 , the base station apparatus 101 notifies DCI via a DLCCcorresponding to the DLCC-1 for which acquisition of the channel stateinformation is desired (step S701). It is shown in FIG. 7 that the basestation apparatus 101 notifies the mobile station apparatus 102 of DCIas a DLCC corresponding to the DLCC-1 for which acquisition of thechannel state information is desired, via the DLCC-1. The mobile stationapparatus 102 performs blind decoding in the DLCC-1 and attempts todetect DCI addressed to its own apparatus. The mobile station apparatus102 which has detected, in the DLCC-1, DCI addressed to its ownapparatus transmits PUSCH on one of ULCCs, referring to informationrelated to uplink assignment included in the DCI (hopping flag, RBassignment information (RB assignment information for a PUSCH), CIF ifCIF is included). In FIG. 7 , the DCI notified from the base stationapparatus 101 via the DLCC-1 indicates that an uplink transmissionresource in the ULCC-1 has been specified.

The mobile station apparatus 102 which has detected the DCI addressed toits own apparatus in the DLCC-1 identifies, in the CQI request fieldincluded in the DCI format, whether it is in a state to report thechannel state information. Here, if the CQI request field from the basestation apparatus 101 is set to “1”, the mobile station apparatus 102generates the channel state information for the DLCC (here, DLCC-1)corresponding to the DLCC-1 on which DCI is transmitted, and reports thegenerated channel state information. Here, the mobile station apparatus102 reports the channel state information using a part or all of theuplink transmission resource on the ULCC-1 assigned by the base stationapparatus 101 (step S702). For example, the mobile station apparatus 102maps the channel state information generated on the PUSCH in the ULCC-1assigned by the base station apparatus 101, and reports it to the basestation apparatus 101.

As thus described, it is possible to flexibly specify, in a system wheretwo or more bands (e.g., component carriers) can be configured which aremeasuring (generating) targets of the channel state information, ameasuring target of the channel state information, by implicitlyinstructing for which DLCC the mobile station apparatus 102 is supposedto transmit the channel state information, based on the DLCC (it mayalso be DLCC in which the DCI addressed to its own apparatus has beendetected by the mobile station apparatus 102) on which the base stationapparatus 101 transmits DCI.

In addition, the mobile station apparatus 102 may generate the channelstate information for the DLCC corresponding to the DLCC on which theDCI addressed to its own apparatus has been detected, and whereby thebase station apparatus 101 can flexibly specify a DLCC generating thechannel state information for the mobile station apparatus 102.Furthermore, it is not necessary to explicitly indicate a DLCC forgenerating the channel state information by the base station apparatus101 (preparation of a bit field for indicating a DLCC is not required),and whereby it is possible to specify, for the mobile station apparatus102, a DLCC for effectively generating the channel state information.

Subsequently, a case will be described where the base station apparatus101 instructs for which DLCC the mobile station apparatus 102 issupposed to generate the channel state information, according to thesearch space on which DCI (or may be the DCI Format0) is transmits.Here, the search space refers to a range (a region) where the PDCCH maybe formed in which the mobile station apparatus 102 performs blinddecoding (attempts to decode the PDCCH addressed to its own apparatus).In other words, the mobile station apparatus 102 performs blind decodingin the search space to detect the PDCCH addressed to its own apparatus.

FIG. 8 is a schematic view illustrating a structure of a PDCCH resourcein a certain subframe (PDCCH resource region, shown by the latticepattern). In FIG. 8 , the mobile station apparatus 102 performs blinddecoding (performs searching, attempts to detect the PDCCH addressed toits own apparatus) in the SS-0 (shown by vertical lines), the SS-1(shown by right-up diagonal lines), and the SS-2 (shown by left-updiagonal lines) of the PDCCH resource region. Here, the search space maybe configured by the base station apparatus 101 to be Cell-specific orUE-specific.

In addition, the search space may be calculated by the mobile stationapparatus 102 based on parameters (e.g., subframe index in which thePDCCH is transmitted, DLCC-specific index provided to each C-RNTI orDLCC, etc) set by the base station apparatus 101. The base stationapparatus 101 and the mobile station apparatus 102 are caused to share asearch space before the mobile station apparatus 102 performs blinddecoding in the search space.

FIG. 9 illustrates another exemplary specification of a DLCC accordingto allocation of DCI according to the second embodiment. FIG. 9illustrates an example in which the base station apparatus 101 specifiesa DLCC for generating the channel state information for the mobilestation apparatus 102 when, for example, the base station apparatus 101communicates with the mobile station apparatus 102 using three DLCCs(e.g., DLCC-0, DLCC-1, and DLCC-2) and two ULCCs (e.g., ULCC-0 andULCC-1).

The SS (search space) illustrated on the left side of FIG. 9 indicates asearch space (it may also be a search space in which the mobile stationapparatus 102 detects DCI addressed to its own apparatus) on which thebase station apparatus 101 transmits DCI, and the CQI referenceresources illustrated on the right side of FIG. 9 indicate a DLCC forthe mobile station apparatus 102 to generate the channel stateinformation, based on the search space (it may also be a search space inwhich the mobile station apparatus 102 detects DCI addressed to its ownapparatus) on which the base station apparatus 101 transmits DCI. Inother words, correspondence (correspondence table, linking) is showninstructing for which DLCC the mobile station apparatus 102 is supposedto generate the channel state information, when the CQI request fieldincluded in the DCI Format0 from the base station apparatus 101 is setto “1”.

For example, as shown in FIG. 9 , upon detecting the DCI addressed toits own apparatus which has been transmitted on the SS-0, and if the CQIrequest field in the DCI is set to “1” by the base station apparatus101, the mobile station apparatus 102 generates the channel stateinformation for the DLCC-0 and reports the generated channel stateinformation. In addition, for example, upon detecting the DCI addressedto its own apparatus which has been transmitted on the SS-1, and if theCQI request field in the DCI is set to “1” by the base station apparatus101, the mobile station apparatus 102 generates the channel stateinformation for the DLCC-2 and reports the generated channel stateinformation. In addition, for example, upon detecting the DCI addressedto its own apparatus which has been transmitted on the SS-2, and if theCQI request field in the DCI is set to “1” by the base station apparatus101, the mobile station apparatus 102 generates the channel stateinformation for the DLCC-1 and reports the generated channel stateinformation.

Here, correspondence (correspondence table, linking) between the searchspace on which the base station apparatus 101 transmits DCI and the DLCCfor the mobile station apparatus 102 to generate the channel stateinformation may be configured by the base station apparatus 101 to beCell-specific or UE-specific. In addition, correspondence(correspondence table, linking) between the search space on which thebase station apparatus 101 transmits DCI and the DLCC for the mobilestation apparatus 102 to generate the channel state information may becalculated by the mobile station apparatus 102 based on parameters(e.g., subframe index in which a PDCCH is transmitted, DLCC-specificindex provided to each C-RNTI, DLCC, etc) set by the base stationapparatus 101.

FIG. 10 is another schematic view illustrating a structure of a PDCCHresource (PDCCH resource region shown by the lattice pattern) in acertain subframe. As shown in FIG. 10 , the base station apparatus 101may transmits DCI (or may be the DCI Format0) across a plurality ofDLCCs. In other words, the mobile station apparatus 102 can perform,across a plurality of DLCCs, blind decoding in the search space on whichthe DCI addressed to its own apparatus may be transmitted, and identify(determine) a DLCC for generating the channel state information based onthe search space in which the DCI addressed to its own apparatus hasbeen detected. In other words, correspondence (correspondence table,linking) between the search space on which the base station apparatus101 transmits DCI (it may also be the search space in which the mobilestation apparatus 102 detects DCI addressed to its own apparatus) andthe DLCC for the mobile station apparatus 102 to generate the channelstate information may be associated across a plurality of DLCCs.

In FIG. 10 , the mobile station apparatus 102 performs blind decoding inthe SS-0 (shown by vertical lines) and the SS-1 (shown by right-updiagonal lines) configured in the PDCCH resource of the DLCC-0 (PDCCHresource region, shown by the lattice pattern). In addition, the mobilestation apparatus 102 performs blind decoding in the SS-2 (shown byleft-up diagonal lines) configured in the PDCCH resource of the DLCC-1(PDCCH resource region, also shown by the lattice pattern).

For example, upon detecting the DCI addressed to its own apparatus whichhas been transmitted on the SS-0, and if the CQI request field in theDCI is set to “1s” by the base station apparatus 101, the mobile stationapparatus 102 generates the channel state information for the DLCC-0 andreports the generated channel state information. In addition, forexample, upon detecting the DCI addressed to its own apparatus which hasbeen transmitted on the SS-1, and if the CQI request field in the DCI isset to “1” by the base station apparatus 101, the mobile stationapparatus 102 generates the channel state information for the DLCC-2 andreports the generated channel state information. In addition, forexample, upon detecting the DCI addressed to its own apparatus which hasbeen transmitted on the SS-2, and if the CQI request field in the DCI isset to “1” by the base station apparatus 101, the mobile stationapparatus 102 generates channel state information for the DLCC-1 andreports the generated channel state information.

Here, it is assumed that the correspondence between the search space onwhich the base station apparatus 101 transmits DCI (it may be the searchspace in which the mobile station apparatus 102 detects DCI addressed toits own apparatus) and the DLCC for the mobile station apparatus 102 togenerate the channel state information is a correspondence such as shownin FIG. 9 .

Here, the correspondence between the search space on which the basestation apparatus 101 transmits DCI and the DLCC for the mobile stationapparatus to generate the channel state information may be such thatDLCCs for generating the channel state information are respectivelyassociated with different search spaces. In addition, the correspondencebetween the search space on which the base station apparatus 101transmits DCI and the DLCC for the mobile station apparatus 102 togenerate the channel state information may be such that a same DLCC forgenerating the channel state information is associated with differentsearch spaces.

In FIG. 10 , for example, if the CQI request field in the DCItransmitted on the SS-1 by the base station apparatus 101 is set to “1”,the mobile station apparatus 102 generates the channel state informationfor the DLCC-1 and reports the generated channel state information. Inaddition, if the CQI request field in the DCI transmitted on the SS-2 bythe base station apparatus 101 is set to “1”, the mobile stationapparatus 102 may generate the channel state information for a sameDLCC-1 and report the generated the channel state information.

Here, the reporting procedure of identifying (determining), by thesearch space on which the base station apparatus 101 transmits DCI (bythe mobile station apparatus 102 detecting the DCI addressed to its ownapparatus), the DLCC for the mobile station apparatus 102 to generatethe channel state information, and reporting the channel stateinformation for the identified DLCC can be realized in a proceduresimilar to the reporting procedure described in FIG. 7 .

Furthermore, the DLCC and the search space on which the base stationapparatus 101 transmits DCI and the DLCC for the mobile stationapparatus 102 to generate the channel state information may beassociated with each other. In other words, the correspondences shown inFIGS. 6 and 9 may be combined for use by providing an index to thesearch space for each DLCC.

For example, upon detecting the DCI addressed to its own apparatus whichhas been transmitted on the SS-0 of the DLCC-0, and if the CQI requestfield in the DCI is set to “1” by the base station apparatus 101, themobile station apparatus 102 may generate the channel state informationfor the DLCC-0 and report the generated channel state information. Inaddition, for example, upon detecting the DCI addressed to its ownapparatus which has been transmitted on the SS-0 of the DLCC-1, and ifthe CQI request field in the DCI is set to “1” by the base stationapparatus 101, the mobile station apparatus 102 may generate the channelstate information for the DLCC-1 and report the generated channel stateinformation. Even if the correspondence between the region on which thebase station apparatus 101 transmits DCI and the DLCC for the mobilestation apparatus 102 to generate the channel state information isprovided in this manner, a similar effect can be obtained.

As thus described, it is possible to flexibly specify measuring targetof the channel state information in a system where two or more bands(e.g., component carriers) can be configured which are measuring(generating) targets of the channel state information, by implicitlyinstructing for which DLCC the mobile station apparatus 102 is supposedto transmit the channel state information, based on the search space onwhich the base station apparatus 101 transmits DCI (it may also be thesearch space in which the mobile station apparatus 102 detects DCIaddressed to its own apparatus).

In addition, the mobile station apparatus 102 may generate the channelstate information for the DLCC corresponding to the search space inwhich the DCI addressed to its own apparatus has been detected, andwhereby the base station apparatus 101 can flexibly specify a DLCC forgenerating the channel state for the mobile station apparatus 102.Furthermore, it is not necessary to explicitly indicate a DLCC forgenerating the channel state information by the base station apparatus101 (preparation of a bit field for indicating a DLCC is not required),and whereby it is possible to specify, for the mobile station apparatus102, a DLCC for effectively generating the channel state information.

As shown in the foregoing, the base station apparatus 101 may transmitsDCI on a certain region (it may be that the mobile station apparatus 102detects DCI addressed to its own apparatus in a certain region) andimplicitly instruct for which DLCC the mobile station apparatus 102 issupposed to transmit the channel state information, and whereby it ispossible to flexibly specify a measuring target of the channel stateinformation in a system where two or more bands (e.g., componentcarriers) can be configured which are measuring (generating) targets ofthe channel state information.

In addition, the mobile station apparatus 102 may generate the channelstate information for the DLCC based on the region in which the DCIaddressed to its own apparatus has been detected, and whereby the basestation apparatus 101 can flexibly configure the DLCC for generating thechannel state information for the mobile station apparatus 102.Furthermore, it is not necessary to explicitly specify a DLCC forgenerating the channel state information (it is not necessary to preparea bit field for specifying a DLCC) by the base station apparatus 101,and it is possible to specify, for the mobile station apparatus 102, aDLCC for effectively generating the channel state information.

Third Embodiment

Next, a third embodiment of the present invention will be described. Inthe first embodiment of the present invention, description has beenprovided such that the base station apparatus 101 transmits the DCIFormat0 including a bit field for indicating whether or not reporting ofthe channel state information is requested, together with a bit field(information) included therein, instructing for which DLCC the mobilestation apparatus 102 is supposed to generate (measure) the channelstate information, and the mobile station apparatus 102 generates thechannel state information for the DLCC instructed by the base stationapparatus 101 and reports the generated channel state information.

Description will be provided for the third embodiment of the presentinvention such that the base station apparatus 101 instructs for whichDLCC the mobile station apparatus 102 is supposed to generate thechannel state information, based on an uplink transmission resource tobe assigned to the mobile station apparatus 102. For example, the basestation apparatus 101 assigns a transmission resource of an uplink tothe mobile station apparatus 102, and the mobile station apparatus 102generates the channel state information for the DLCC corresponding tothe ULCC (forming a pair with the ULCC) on which the uplink transmissionresource has been assigned by the base station apparatus 101 (to put itanother way, an uplink transmission resource has been mapped), andreports the generated channel state information.

A radio communication system according to the third embodiment can beimplemented by a configuration similar to that of the radiocommunication system shown in FIG. 1 . FIG. 11 illustrates an exemplarypair (also referred to as CC pair, correspondence of CC, or a linking ofCC) of a downlink component carrier (DLCC) and an uplink componentcarrier (ULCC) according to the third embodiment. FIG. 11 illustrates anexample in which the base station apparatus 101 specifies a DLCC forgenerating the channel state information for the mobile stationapparatus 102 when, for example, the base station apparatus 101communicates with the mobile station apparatus 102 using three DLCCs(e.g., DLCC-0, DLCC-1, and DLCC-2) and two ULCCs (e.g., ULCC-0 andULCC-1).

The pair (index) shown in FIG. 11 indicates a pair (correspondence orlinking) of a DLCC for the mobile station apparatus 102 to generate thechannel state information and a ULCC which the base station apparatus101 assigns the uplink transmission resource to the mobile stationapparatus 102. The base station apparatus 101 may configure a pair ofDLCC and ULCC by notifying the mobile station apparatus 102 of the pair(index). The base station apparatus 101 can configure, for the mobilestation apparatus 102, a pair of DLCC and ULCC to be Cell-specific orUE-specific.

In addition, the base station apparatus 101 may configure a pair of DLCCand ULCC for the mobile station apparatus 102 in a semi-static ordynamic manner. In addition, the base station apparatus 101 may transmitparameters (e.g., subframe index in which a PDCCH is transmitted,DLCC-specific index provided to each C-RNTI or DLCC, ULCC-specific indexprovided to each ULCC, etc) for configuring a pair of DLCC and ULCC tothe mobile station apparatus 102, and a pair of DLCC and ULCC may becalculated by the mobile station apparatus 102. The base stationapparatus 101 and the mobile station apparatus 102 are caused to share apair of ULCC and DLCC before the base station apparatus 101 notifies theDCI.

In addition, the DLCC shown in FIG. 11 indicates a DLCC for generatingthe channel state information by the mobile station apparatus 102, whichcorresponds to the ULCC on which the uplink transmission resource isassigned by the base station apparatus 101. In addition, the ULCC shownin FIG. 11 indicates a ULCC on which the uplink transmission resource isassigned by the base station apparatus 101. In other words, FIG. 11illustrates the correspondence (correspondence table, linking)instructing for which DLCC the mobile station apparatus 102 is supposedto generate the channel state information, if the CQI request fieldincluded in the DCI Format0 from the base station apparatus 101 is setto “1”.

Here, the uplink transmission resource which the base station apparatus101 assigns to the mobile station apparatus 102 includes, for example,the PUSCH resource or the PUCCH resource. As described above, the basestation apparatus 101 can assign the uplink transmission resource basedon the DCI Format0 including the CIF field. In addition, the basestation apparatus 101 can assign the uplink transmission resource basedon the DCI Format0 not including the CIF field. The mobile stationapparatus 102 generates the channel state information for the DLCCcorresponding to the ULCC on which the PUSCH resource or the PUCCHresource has been assigned by the base station apparatus 101, andreports the generated channel state information to the base stationapparatus 101.

For example, in FIG. 11 , if the uplink transmission resource on theULCC-0 has been assigned by the base station apparatus 101, the mobilestation apparatus 102 generates the channel state information for theDLCC-0, and reports the generated channel state information. Inaddition, for example, if the uplink transmission resource on the ULCC-1has been assigned by the base station apparatus 101, the mobile stationapparatus 102 generates the channel state information for the DLCC-1 andreports the generated channel state information. In addition, forexample, if the uplink transmission resource on the ULCC-1 has beenassigned by the base station apparatus 101, the mobile station apparatus102 generates the channel state information for the DLCC-2 and reportsthe generated channel state information. Here, the CQI request fieldincluded in the DCI Format0 transmitted from the base station apparatus101 is set to “1”.

FIG. 12 illustrates an exemplary reporting procedure of the channelstate information according to the third embodiment. The base stationapparatus 101 notifies the mobile station apparatus 102 of the DCIincluding uplink-related information for the ULCC forming a pair with(corresponding to) the DLCC for which acquisition of the channel stateinformation is desired. In other words, the base station apparatus 101assigns, to the mobile station apparatus 102, the uplink transmissionresource on the ULCC forming a pair with the DLCC for which acquisitionof the channel state information is desired.

For example, the base station apparatus 101 assigns the uplinktransmission resource on the ULCC forming a pair with the DLCC based onthe resource assignment information included in the DCI Format0, andfurther, specifies a state to report the channel state information inthe CQI request field in the DCI Format 0 (sets the CQI request field to1).

In FIG. 12 , the base station apparatus 101 assigns the uplinktransmission resource on the ULCC-1 corresponding to the DLCC-1 and theDLCC-2 for which acquisition of the channel state information is desired(step 1201). FIG. 12 illustrates that the base station apparatus 101assigns the uplink transmission resource on the ULCC-1 based on the DCI(or may be the DCI Format0) mapped on the DLCC-0. The mobile stationapparatus 102 performs blind decoding in the DLCC-0, and attempts todetect DCI addressed to its own apparatus. The mobile station apparatus102 which has detected the DCI addressed to its own apparatus in theDLCC-0 transmits the PUSCH in one of ULCCs, referring to informationrelated to the uplink assignment included in the DCI Format 0 (hoppingflag, RB assignment information (e.g., RB assignment information for aPUSCH, RB assignment information for a PUCCH), CIF if CIF is included).FIG. 12 illustrates that the DCI notified from the base stationapparatus 101 via the DLCC-0 has specified therein the uplinktransmission resource on the ULCC-1.

The mobile station apparatus 102 which has detected the DCI addressed toits own apparatus in the DLCC-0 identifies whether or not the CQIrequest field included in the DCI Format 0 is in a state to report thechannel state information. Here, if the CQI request field from the basestation apparatus 101 is set to “1”, the mobile station apparatus 102generates the channel state information for the DLCC-1 and/or the DLCC-2corresponding to the ULCC-1 which the base station apparatus 101 hasassigned the uplink transmission resource, and reports the channel stateinformation, using a part or all of the assigned uplink transmissionresource (step S1202). For example, the mobile station apparatus 102maps the generated channel state information to the PUSCH resource onthe ULCC-1 assigned by the base station apparatus 101, and reports it tothe base station apparatus 101.

As shown in the foregoing, the base station apparatus 101 may assign theuplink transmission resource on the ULCC and implicitly instruct forwhich DLCC the mobile station apparatus 102 is supposed to transmit thechannel state information, and whereby it is possible to flexiblyspecify a measuring target of the channel state information in a systemwhere two or more bands (e.g., component carriers) can be configuredwhich are measuring (generating) targets of the channel stateinformation.

In addition, the mobile station apparatus 102 may generate the channelstate information for the DLCC corresponding to the ULCC which the basestation apparatus 101 has assigned the uplink transmission resource, andwhereby the base station apparatus 101 can flexibly specify a DLCC forwhich the channel state information is generated for the mobile stationapparatus 102. Furthermore, it is not necessary to explicitly indicate aDLCC for generating the channel state information by the base stationapparatus 101 (preparation of a bit field for indicating a DLCC is notrequired), and whereby it is possible to specify, for the mobile stationapparatus 102, a DLCC for effectively generating the channel stateinformation.

Although the foregoing description has explained a method of specifyinga single DLCC for the mobile station apparatus 102 to generate thechannel state information, in association with a single ULCC in whichthe base station apparatus 101 assigns a single uplink transmissionresource, the method is not limited thereto. For example, a DLCC for themobile station apparatus 102 to generate the channel state informationmay be specified by associating a plurality of uplink transmissionresources in a single ULCC with a plurality of DLCCs. In addition, asimilar effect can be obtained by associating a plurality of uplinktransmission resources in a plurality of ULCCs with a plurality of DLCCsto specify a DLCC for the mobile station apparatus 102 to generate thechannel state information.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be described. Inthe first embodiment of the present invention, description has beenprovided such that the base station apparatus 101 transmits the DCIFormat0 including a bit field for indicating whether or not reporting ofthe channel state information is requested, together with a bit field(information) included therein, instructing for which DLCC the mobilestation apparatus 102 is supposed to generate (measure) the channelstate information, and the mobile station apparatus 102 generates thechannel state information for the DLCC instructed by the base stationapparatus 101 and reports the generated channel state information.

Description will be provided for the fourth embodiment of the presentinvention such that the base station apparatus 101 instructs for whichDLCC the mobile station apparatus 102 is supposed to generate thechannel state information, according to the CIF indicating the ULCC onwhich the PUSCH to be assigned to the mobile station apparatus 102 ismapped. For example, the base station apparatus 101 notifies the CIFindicating the ULCC on which the PUSCH to be assigned to the mobilestation apparatus 102 is mapped, and the mobile station apparatus 102generates the channel state information for the DLCC based on the CIFnotified by the base station apparatus 101 (to put it another way, aDLCC corresponding to the ULCC indicated by the CIF), and reports thegenerated channel state information.

A radio communication system according to the fourth embodiment can beimplemented by a configuration similar to that of the radiocommunication system shown in FIG. 1 . FIG. 13 illustrates an exemplaryreporting procedure of the channel state information according to thepresent embodiment. FIG. 13 illustrates an example in which the basestation apparatus 101 specifies a DLCC for generating the channel stateinformation for the mobile station apparatus 102 when, for example, thebase station apparatus 101 communicates with the mobile stationapparatus 102 using three DLCCs (e.g., DLCC-0, DLCC-1, and DLCC-2) andtwo ULCCs (e.g., ULCC-0 and ULCC-1).

In FIG. 13 , each of the DLCCs and ULCCs has at least one CarrierIndicator (also referred to as carrier index) mapped (provided) thereto.FIG. 13 illustrates an example in which 000 is mapped to DLCC-0, 010 ismapped to DLCC-1, and 111 is mapped to DLCC-2. In addition, an exampleis illustrated in which 000 is mapped to the ULCC-0, and 010 and/or 111is mapped to ULCC-1. In FIG. 13 , although carrier indicators asdescribed above are mapped to the DLCCs and the ULCCs as an example, itis needless to say that carrier indicators to be mapped to the DLCCs andthe ULCCs are not limited thereto.

Here, the base station apparatus 101 may configure, for the mobilestation apparatus 102, the mapping between the DLCCs and the ULCCs, andthe carrier indicators to be Cell-specific or UE-specific. The basestation apparatus 101 and the mobile station apparatus 102 are supposedto have shared the mapping between the DLCCs and the ULCCs, and thecarrier indicators before the base station apparatus 101 notifies theDCI Format0. In addition, the base station apparatus 101 may set, forthe mobile station apparatus 102, the mapping between the DLCCs and theULCCs, and the carrier indicators in a semi-static or a dynamic manner.

In FIG. 13 , a carrier indicator (a value of a carrier indicator) mappedto a DLCC and a carrier indicator (a value of a carrier indicator)mapped to a ULCC are associated with each other. In other words, a DLCCand a ULCC having a same carrier indicator (having a same value of acarrier indicator) are associated with each other. In other words, aDLCC and a ULCC having mapped thereto a same carrier indicator areassociated with each other.

In FIG. 13 , the DLCC-0 having carrier indicator 000 mapped thereto andthe ULCC-0 having the carrier indicator 000 mapped thereto areassociated with each other. In addition, the DLCC-1 having the carrierindicator 010 mapped thereto and the ULCC-1 having the carrier indicator010 (carrier indicator 010 and/or 111) mapped thereto are associatedwith each other. In addition, the DLCC-2 having the carrier indicator111 mapped thereto and the ULCC-1 having the carrier indicator 111(carrier indicator 010 and/or 111) mapped thereto are associated witheach other.

The base station apparatus 101 assigns the uplink transmission resourceto the mobile station apparatus 102 using the downlink controlinformation format including a CIF field. For example, the base stationapparatus 101 assigns the uplink transmission resource to the mobilestation apparatus 102 using the downlink control information format asillustrated on the right side of FIG. 4 . As described above, the basestation apparatus 101 can indicate, to the mobile station apparatus 102,a ULCC having allocated thereto the uplink transmission resource (e.g.,the PUSCH resource), by transmitting the downlink control informationformat together with CIF included therein. In other words, the basestation apparatus 101 can indicate, to the mobile station apparatus 102,a ULCC having a carrier indicator mapped thereto, by indicating acarrier indicator (a value thereof) using the CIF.

Referring to FIG. 13 , an exemplary reporting procedure of channel stateinformation according to the third embodiment will be described. Thebase station apparatus 101 notifies the mobile station apparatus 102 ofDCI including uplink-related information for a ULCC having mappedthereto a same carrier indicator (a value of which) as that of the DLCCfor which acquisition of the channel state information is desired. Toput it another way, the base station apparatus 101 notifies the mobilestation apparatus 102 of the downlink control information formatincluding a carrier indicator (a value of which) mapped to a DLCC forwhich acquisition of the channel state information is desired. Forsimplicity in the following, the downlink control information format isdenoted as the DCI Format0.

For example, the base station apparatus 101 notifies the mobile stationapparatus 102 of a ULCC having mapped thereto a same carrier indicator(a value of which) as that of the DLCC for which acquisition of channelstate information is desired, using the CIF included in the DCI Format0.In this occasion, the base station apparatus 101 specifies a state toreport the channel state information in the CQI request field in the DCIFormat 0 (the CQI request field is set to “1”).

In FIG. 13 , for example, the base station apparatus 101 assigns theuplink transmission resource of the ULCC-1 having mapped thereto a samecarrier indicator (111) as the carrier indicator (111) mapped to theDLCC-2 for which acquisition of the channel state information is desired(step S1301). For example, the base station apparatus 101 sets the valueof the CIF included in the DCI Format0 to 111 and assigns the PUSCHresource to the mobile station apparatus 102. The mobile stationapparatus 102 performs blind decoding in the DLCC-0 and attempts todetect DCI addressed to its own apparatus. The mobile station apparatus102 which has detected the DCI addressed to its own apparatus in theDLCC-0 transmits the PUSCH in one of the ULCCs, referring to informationrelated to an uplink assignment included in the DCI Format 0 (hoppingflag, RB assignment information (e.g., RB assignment information for aPUSCH), CIF). FIG. 13 illustrates that to the DCI notified from the basestation apparatus 101 via the DLCC-0, an uplink transmission resource inthe ULCC-1 is specified.

The mobile station apparatus 102 identifies whether or not the CQIrequest field included in the DCI Format 0 notified via the DLCC-0 is ina state to report the channel state information. Here, if the CQIrequest field is in a state to report the channel state information, themobile station apparatus 102 generates the channel state information forthe DLCC having mapped thereto a same carrier indicator as that of theULCC indicated by the CIF from the base station apparatus 101, andreports the channel state information, using a part or all of theassigned uplink transmission resource (step S1302).

The mobile station apparatus 102 which has detected the DCI addressed toits own apparatus in the DLCC-0 identifies whether the CQI request fieldincluded in the DCI Format 0 is in a state to report the channel stateinformation. Here, if the CQI request field from the base stationapparatus 101 is set to “1”, the mobile station apparatus 102 generateschannel state information for the DLCC having mapped thereto a samecarrier indicator as that of the ULCC indicated by the CIF from the basestation apparatus 101, and reports the channel state information, usinga part or all of the assigned uplink transmission resources. Forexample, the mobile station apparatus 102 maps the generated channelstate information to the PUSCH resource in the ULCC-1 assigned by thebase station apparatus 101, and reports it to the base station apparatus101 (step S1302).

Furthermore, another example will be described. The following describesan example in which the base station apparatus 101 specifies a DLCC forgenerating the channel state information for the mobile stationapparatus 102, when the base station apparatus 101 communicates with themobile station apparatus 102 using three DLCCs (e.g., DLCC-0, DLCC-1,and DLCC-2) and three ULCCs (e.g., ULCC-0, ULCC-1, and ULCC-2).

Here, as an example, the carrier indicator 000 is mapped to the DLCC-0,the carrier indicator 010 is mapped to the DLCC-1, and the carrierindicator 111 is mapped to the DLCC-2 by the base station apparatus 101.In addition, the carrier indicator 000 is mapped to the ULCC-0, the thecarrier indicator 010 is mapped to the ULCC-1, and the carrier indicator111 is mapped to the ULCC-2 by the base station apparatus 101. Asdescribed above, a DLCC and a ULCC having a same carrier indicator (asame value of a carrier indicator) are associated with each other. Inother words, a DLCC and a ULCC having mapped thereto a same carrierindicator are associated with each other.

Here, the base station apparatus 101 can link a DLCC and a ULCC in aCell-specific or UE-specific manner. For example, the base stationapparatus 101 can provide a linking between the DLCC-1 and the ULCC-4,and between the DLCC-1 and the ULCC-1. In addition, the base stationapparatus 101 assigns the uplink transmission resource to the mobilestation apparatus 102. For example, the base station apparatus 101transmits, via the DLCC-1, the DCI Format0 including the RB assignmentinformation for the PUSCH, and assigns the PUSCH resource to the mobilestation apparatus 102.

The base station apparatus 101 sets the value of the CIF included in theDCI Format0 to the value of the carrier indicator mapped to one of theULCCs which have been linked to the DLCCs, and notifies it to the mobilestation apparatus 102. For example, the base station apparatus 101 setsthe value of the CIF included in the DCI Format0 to the value of thecarrier indicator mapped to the ULCC-1 linked to the DLCC-1, or mappedto the ULCC-0 linked to the DLCC-1 and notifies it to the mobile stationapparatus 102.

In other words, the base station apparatus 101 sets the value of the CIFincluded in the DCI Format0 to 000 (carrier indicator mapped to ULCC-0)or 010 (carrier indicator mapped to ULCC-1), and notifies it to themobile station apparatus 102. To put it another way, the base stationapparatus 101 does not set the value of the CIF included in the DCIFormat0 to 111 (carrier indicator mapped to ULCC-1).

The mobile station apparatus 102 generates the channel state informationfor the DLCC having mapped thereto a same carrier indicator as that ofthe ULCC indicated by the CIF from the base station apparatus 101, andreports the generated channel state information. In other words, if thevalue of the CIF included in the DCI Format0 from the base stationapparatus 101 is set to 000, the mobile station apparatus 102 generatesthe channel state information for the DLCC-0 and reports the generatedchannel state information. In addition, if the value of the CIF includedin the DCI Format0 from the base station apparatus 101 is set to 010,the mobile station apparatus 102 generates the channel state informationfor the DLCC-1 and reports the generated channel state information tothe base station apparatus 101.

Here, the mobile station apparatus 102 maps the channel stateinformation to the uplink transmission resource (e.g., the PUSCHresource), based on the uplink transmission resource (e.g., RBassignment information to PUSCH) included in the DCI Format0 from thebase station apparatus 101, and transmits it to the base stationapparatus 101.

In other words, the base station apparatus 101 can provide a linkingbetween the DLCC and the ULCC in a Cell-specific or UE-specific manner.Furthermore, the base station apparatus 101 can set the value of the CIFincluded in the DCI Format0 to the value of the carrier indicator mappedto one of the ULCCs which are linked to the DLCC, and notify it to themobile station apparatus 102. In addition, the mobile station apparatus102 can generate the channel state information for the DLCC havingmapped thereto a same carrier indicator as that of the ULCC indicated bythe CIF from the base station apparatus 101, and report the generatedchannel state information.

As thus described, the base station apparatus 101 may specify, for themobile station apparatus 102, a DLCC for generating the channel stateinformation, and whereby the base station apparatus 101 can specify aDLCC for generating the channel state information with a higherprecision. For example, upon detecting a value of the CIF included inthe DCI Format0 from the base station apparatus 101 as a valueindicating a ULCC which is not (preliminarily) linked (if, for example,a value of the CIF is detected as 111 (carrier indicator mapped to theULCC-2)), the mobile station apparatus 102 can avoid transmission of thechannel state information unintended by the base station apparatus 101by not transmitting the channel state information.

As shown in the foregoing, using the CIF included in the downlinkcontrol information format by which assigning the uplink transmissionresource, the base station apparatus 101 may implicitly instruct forwhich DLCC the mobile station apparatus 102 is supposed to transmit thechannel state information, and whereby it is possible to flexiblyspecify, in a system where two or more bands (e.g., component carriers)can be configured which are measuring (generating) targets of thechannel state information.

In addition, the mobile station apparatus 102 may generate the channelstate information for the DLCC having mapped thereto a same carrierindicator as that of the ULCC that is indicated in CIF from the basestation apparatus 101, and whereby the base station apparatus 101 canflexibly specify a DLCC for generating the channel state information forthe mobile station apparatus 102. Furthermore, it is not necessary toexplicitly indicate a DLCC to generate the channel state information bythe base station apparatus 101 (preparation of a bit field forindicating a DLCC is not required), and whereby it is possible tospecify, for the mobile station apparatus 102, a DLCC for effectivelygenerating the channel state information.

Although the foregoing description has explained a method of generating,by the mobile station apparatus 102, the channel state information for aDLCC having mapped thereto a same carrier indicator as that of the ULCCspecified in the CIF from the base station apparatus 101, the method isnot limited thereto. For example, a predetermined parameter (e.g., anoffset) may be set by the base station apparatus 101, and the mobilestation apparatus 102 may identify (determine) a DLCC for generating thechannel state information, based on the CIF from the base stationapparatus 101 and a predetermined parameter.

Fifth Embodiment

Next, a fifth embodiment of the present invention will be described. Inthe first embodiment of the present invention, description has beenprovided such that the base station apparatus 101 transmits the DCIFormat0 including a bit field for indicating whether or not reporting ofthe channel state information is requested, together with a bit field(information) included therein, instructing for which DLCC the mobilestation apparatus 102 is supposed to generate (measure) the channelstate information, and the mobile station apparatus 102 generates thechannel state information for the DLCC instructed by the base stationapparatus 101 and reports the generated channel state information.

In the fifth embodiment of the present invention, description isprovided in which the base station apparatus 101 (re)uses theinformation included in the downlink control information format toinstruct for which DLCC the mobile station apparatus 102 is supposed togenerate the channel state information. In other words, the base stationapparatus 101 can (re)use an existing bit field (a predetermined bitfield) to instruct for which DLCC the mobile station apparatus 102 issupposed to generate the channel state information. For example, thebase station apparatus 101 can specify a DLCC for the mobile stationapparatus 102 to generate the channel state information by setting theRB assignment field, and/or, the MCS field, and/or, the CQI requestfield included in the DCI Format0 to a specific value (setting apredetermined first field(s) to a predetermined value) and further, inthis occasion, (re)using a New Data Indicator field (a predeterminedsecond field) as a field for specifying a DLCC.

In other words, if the RB assignment field, and/or, the MCS field,and/or, the CQI request field (a predetermined first field (s)) includedin the DCI Format0 are set to a value other than a specific value (apredetermined value), to a certain field (a predetermined second field)information indicating initial transmission or re-transmission is set(used as a New Data Indicator field). In addition, if the RB assignmentfield, and/or, the MCS field, and/or, the CQI request field included inthe DCI Format0 (a predetermined first field(s)) are set to a specificvalue (a predetermined value), to a certain field (a predeterminedsecond field) information specifying a DLCC for the mobile stationapparatus 102 to generate the channel state information by is set.

In other words, the mobile station apparatus 102 changes theinterpretation of the information which is set in a certain field,depending on whether the RB assignment field, and/or, the MCS field,and/or, the CQI request field included in the DCI Format0 are set to avalue other than a specific value, or set to a specific value. In otherwords, the mobile station apparatus 102 can change the interpretation ofthe information which is set in a certain field to informationindicating initial transmission or re-transmission, or informationspecifying a DLCC for generating the channel state information.

A radio communication system according to the fifth embodiment can beimplemented by a configuration similar to that of the radiocommunication system shown in FIG. 1 . FIG. 14 illustrates an exemplaryconfiguration of the DCI Format0 according to the fifth embodiment.

As shown in FIG. 14 , the DCI Format0, including uplink-relatedinformation such as uplink scheduling information, includes (is formedby) a flag (Flag for Format0/Format1A) for distinguishing between theDCI Format0 and a Format1A which is another downlink control informationformat, a bit field indicating uplink scheduling such as a Hopping flag,RB assignment information (Resource block assignment) or the like; anMCS (Modulation and Coding Scheme) and RV (Redundancy Version) bit fieldindicating modulation scheme and coding rate, parameters forretransmission or the like; a New Data Indicator bit field indicatingwhether the transmission is initial transmission or re-transmission; aCQI request bit field indicating whether or not reporting of the channelstate information (channel quality indicator) is requested; a TPC(Transmission Power Control) command bit indicating uplink transmitpower; a Cyclic shift for ULRS bit field indicating a resource of anuplink reference signal, or the like.

For example, when instructing, by uplink scheduling information, themobile station apparatus 102 to transmit only the control informationsuch as the channel state information, the base station apparatus 101sets a certain field as information indicating a DLCC for generating thechannel state information. For example, the base station apparatus 101instructs the mobile station apparatus 102 to transmit only the controlinformation by assigning the number of fields for the RB assignmentinformation included in the DCI Format0 to be equal to or smaller than apredetermined number of RBs (e.g., setting the number of RB assignmentfields equal to or smaller than 4 RBs) and setting the field for MCS andRV to a predetermined value (e.g., setting the MCS and RV field to 29),and setting the CQI request field to “1”.

In this occasion, the base station apparatus 101 further sets, in theNew Data Indicator field included in the DCI Format0, informationinstructing for which DLCC the mobile station apparatus 102 is supposedto generate the channel state information, and notifies it to the mobilestation apparatus 102. In other words, in this occasion, interpretationof the New Data Indicator field is changed to a field instructing forwhich DLCC the mobile station apparatus 102 is supposed to generate thechannel state information.

Here, it is predetermined by specifications or the like and supposed tohave preliminarily been shared between the base station apparatus 101and the mobile station apparatus 102 the recognition of which field theinterpretation thereof is supposed to be changed when any field includedin the DCI Format0 is set to any value.

The mobile station apparatus 102 checks a predetermined field in orderto detect the DCI Format0 addressed to its own apparatus and determineinterpretation of a certain field. For example, the mobile stationapparatus 102 first checks the field for RB assignment information, thefield for MCS and RV, and the CQI request field, in order to determinewhether a certain field should be interpreted as a New Data Indicatorfield, or as a field instructing which DLCC the channel stateinformation is supposed to be generated for.

The mobile station apparatus 102 checks a predetermined field and, if itis necessary to transmit the channel state information for the DLCCinstructed by the base station apparatus 101, transmits the PUSCH in oneof ULCCs, referring to information related to an uplink assignmentincluded in the DCI Format0 (hopping flag, RB assignment information(e.g., RB assignment information for a PUSCH, RB assignment informationfor a PUCCH), CIF if CIF is included).

If, in this occasion, transmission of only the control information isinstructed from the base station apparatus 101, the mobile stationapparatus 102 maps only the control information to the PUSCH resourceand transmits it. For example, the mobile station apparatus 102generates the channel state information for the DLCC instructed by thebase station apparatus 101, maps only the generated channel stateinformation to the PUSCH resource and transmits it. In addition, forexample, the mobile station apparatus 102 generates the channel stateinformation for the DLCC instructed by the base station apparatus 101and, if it is necessary to transmit information indicating an ACK orNACK (ACK/NACK signal, affirmative acknowledge or negative acknowledge)for the downlink data when reporting the generated channel stateinformation, maps the channel state information and the informationindicating the ACK or NACK to the PUSCH resource, and transmits it tothe base station apparatus 101.

Here, the base station apparatus 101 may set, directly in a certainfield, information instructing for which DLCC the mobile stationapparatus 102 is supposed to generate the channel state information.Alternatively, the base station apparatus 101 may set, indirectly in acertain field, information instructing for which DLCC the mobile stationapparatus 102 is supposed to generate channel state information.

For example, if a value set in a certain field is “1”, the base stationapparatus 101 and the mobile station apparatus 102 generate the channelstate information for the DLCC-0 and, if a value set in a certain fieldis “0”, they can preliminarily share the recognition of generating thechannel state information for the DLCC-1 and the DLCC-2. In addition,if, for example, a value set in a certain field is “0”, the base stationapparatus 101 and the mobile station apparatus 102 can preliminarilyshare the recognition of generating the channel state information forall the DLCCs (the channel state information for the DLCC-0, the DLCC-1,and the DLCC-2). In other words, correspondence between value set in acertain field and a DLCC for which the mobile station apparatus 102generates the channel state information can be predetermined.

In other words, if a predetermined value is set in a certain field bythe base station apparatus 101, the mobile station apparatus 102 canalso report the channel state information for a plurality of DLCCs. Forexample, if “0” is set in a certain field by the base station apparatus101, the mobile station apparatus 102 may generate the channel stateinformation for the DLCC activated by the base station apparatus 101,and report the generated channel state information.

For example, as described above, if it has been determined to change theinterpretation of the New Data Indicator field to a field indicating aDLCC for generating the channel state information, by setting the fieldfor RB assignment information, and/or, the field for MCS and RV, and/or,the CQI request field to a specific value by the base station apparatus101, the base station apparatus 101 can instruct the mobile stationapparatus 102 to generate the channel state information for theactivated DLCC, by setting “1” as the value of a field indicating theDLCC for generating the channel state information (to put it anotherway, New Data Indicator field).

Here, the base station apparatus 101 can activate or deactivate theDLCC(s) for the mobile station apparatus 102. For example, the basestation apparatus 101 activates a DLCC which is used to transmit thedownlink signal (e.g., the PDCCH and/or the PDSCH) to the mobile stationapparatus 102. On the other hand, the base station apparatus 101deactivates a DLCC which is not used to transmit the downlink signal(e.g., the PDCCH and/or the PDSCH) to the mobile station apparatus 102.The mobile station apparatus 102 attempts to detect the downlink signalon the activated DLCC. On the other hand, the mobile station apparatus102 does not attempt to detect the downlink signal on the deactivatedDLCC.

In other words, upon detecting the DCI Format0 and, if a specific fieldhas been set to a specific value, the mobile station apparatus 102generates the channel state information for the activated DLCC(s), andreports the generated channel state information. Here, upon detectingthe DCI Format0 and, if a specific field has been set by to a specificvalue, the mobile station apparatus 102 may transmit informationindicating that the DLCC has been deactivated (may transmit it asinformation for checking that the DLCC has been deactivated) byreporting the channel state information for the deactivated DLCC (s) asa specific cord word (e.g., reporting channel state information set to0000).

Here, when instructed to generate the channel state information for theDLCC which has been deactivated by the base station apparatus 101, themobile station apparatus 102 may ignore the instruction. For example,when instructed to generate the channel state information for the DLCCwhich has been deactivated by the DCI Format0 from the base stationapparatus 101, the mobile station apparatus 102 may ignore theinstruction.

In addition, when instructed to generate the channel state informationfor the DLCC which has been deactivated by the base station apparatus101, the mobile station apparatus 102 may activate the DLCC to generatethe channel state information, and report the generated channel stateinformation. For example, when instructed to generate the channel stateinformation for the DLCC which has been deactivated by the DCI Format0from the base station apparatus 101, the mobile station apparatus 102may activate the DLCC to generate the channel state information, andreport the generated channel state information.

Here, although the foregoing description has explained a method ofreusing the New Data Indicator field (changing the interpretation of theNew Data Indicator field to an information field indicating a DLCC forgenerating the channel state information) by the base station apparatus101 and the mobile station apparatus 102, the method is not limitedthereto.

For example, if a specific field has been set to a specific value, thebase station apparatus 101 and the mobile station apparatus 102 maychange the interpretation of the TPC command field or the Cyclic shiftfor ULRS field to an information field indicating a DLCC for generatingthe channel state information. In addition, a plurality of fields whichare combinations of the New Data Indicator field, the TPC command field,and the Cyclic shift for ULRS field may be interpreted as an informationfield indicating a DLCC for generating the channel state information.

As has been shown in the foregoing, the base station apparatus 101 may(re)use a field included in the downlink control information format toinstruct which DLCC the mobile station apparatus 102 is supposed togenerate the channel state information for, whereby it is possible toflexibly specify, in a system having two or more bands (e.g., componentcarriers) that can be configured for measuring (generating) the channelstate information.

In addition, the mobile station apparatus 102 may change theinterpretation of the field included in the downlink control informationformat from the base station apparatus 101 and generate the channelstate information for a DLCC, according to a value set in the changedfield, whereby the base station apparatus 101 can flexibly specify theDLCC for which the mobile station apparatus 102 is supposed to generatethe channel state information. Furthermore, it is not necessary toexplicitly indicate a DLCC for generating the channel state informationby the base station apparatus 101 (preparation of a bit field forindicating a DLCC is not required), whereby it is possible to specify,for the mobile station apparatus 102, a DLCC for effectively generatingthe channel state information.

Furthermore, the mobile station apparatus 102 may change theinterpretation of the field included in the downlink control informationformat from the base station apparatus 101 and generate the channelstate information for plurality of DLCCs, according to a value set inthe changed field, whereby the base station apparatus 101 can flexiblyspecify a plurality of DLCCs for which the mobile station apparatus 102is supposed to generate the channel state information. Furthermore, itis not necessary to explicitly indicate a plurality of DLCCs forgenerating the channel state information by the base station apparatus101 (preparation of a bit field for indicating a plurality of DLCCs isnot required), whereby it is possible to specify, for the mobile stationapparatus 102, a plurality of DLCCs for effectively generating thechannel state information.

Although a case has been explained, in each of the embodiments describedabove, where the base station apparatus 101 includes the CIF in thedownlink control information format to be transmitted to the mobilestation apparatus 102, the base station apparatus 101 and the mobilestation apparatus 102 can preliminarily share the recognition that thedownlink control information format does not include the CIF field whentransmitting on the Cell-specific SS (CSS). In addition, the basestation apparatus 101 and the mobile station apparatus 102 canpreliminarily share the recognition that the downlink controlinformation format include the CIF field when transmitting on theUE-specific SS (USS).

In other words, the base station apparatus 101 can allocate the downlinkcontrol information format not including the CIF on the Cell-specific SSand transmit it to the mobile station apparatus 102. Alternatively, thebase station apparatus 101 can allocate the downlink control informationformat including the CIF on the UE-specific SS and transmit it to themobile station apparatus 102.

FIG. 15 illustrates whether or not the CIF is included in the downlinkcontrol information format, when the base station apparatus 101allocates the downlink control information format on the Cell-specificSS or the UE-specific SS. The base station apparatus 101 and the mobilestation apparatus 102 can preliminarily share the relation between thesearch space such as that shown in FIG. 15 and the CIF included in thedownlink control information format.

As shown in FIG. 15 , for example, the base station apparatus 101transmits, to the mobile station apparatus 102, the downlink controlinformation format to be allocated on the Cell-specific SS withoutincluding the CIF therein (non-existent). Alternatively, for example,the base station apparatus 101 transmits, to the mobile stationapparatus 102, the downlink control information format to be allocatedon UE-specific SS without including the CIF (non-existent) or includingthe CIF (existent). As thus described, the base station apparatus 101may limit the downlink control information format including the CIF ornot including the CIF, according to the search space to be allocated,whereby it becomes possible to decode the downlink control informationformat (may also be downlink control information) allocated on theCell-specific SS, even if the mobile station apparatus 102 does notsupport the downlink control information format including the CIF.

Sixth Embodiment

In the sixth embodiment of the present invention, a block configurationof the base station apparatus 101, a block configuration of the mobilestation apparatus 102, and the function of respective blocks will bedescribed.

FIG. 16 illustrates an exemplary block configuration of the base stationapparatus 101 according to the present embodiment. The base stationapparatus 101 has a higher layer 1601, a scheduling unit 1602, atransmitting unit (downlink transmitting unit, base station transmittingunit) 1603, a receiving unit (uplink receiving unit, base stationreceiving unit) 1604, and an antenna unit (base station antenna unit)1605. The higher layer 1601 has a CC control unit 1606. The schedulingunit 1602 has an uplink control information control unit 1607, adownlink transmission resource information control unit 1608, and adownlink control channel control unit 1609. The transmitting unit 1603has a mapping unit (downlink mapping unit) 1610, and a radiotransmitting unit (downlink radio transmitting unit) 1611. The receivingunit 1604 has a radio receiving unit (uplink radio receiving unit) 1612,a demapping unit (uplink demapping unit) 1613, a demodulation unit 1614,and a decoding unit 1615.

The CC control unit 1606 of the higher layer 1601 manages the DLCC andthe ULCC supported by the base station apparatus 101, and controls theDLCC and the ULCC used for communication with the mobile stationapparatus 102. Based on information acquired from the higher layer 1601,the scheduling unit 1602 determines whether or not to cause each mobilestation apparatus 102 to report the channel state information, anddetermines an uplink transmission resource to be assigned to each mobilestation apparatus 102. In addition, the scheduling unit 1602 generatesdownlink control information for notifying the mobile station apparatus102 of the determined uplink transmission resource. Furthermore, whenretrieving data from a reception signal which has been received from themobile station apparatus 102, the scheduling unit 1602 controlsseparation of the reception signal, based on the determined uplinktransmission resource.

The uplink control information control unit 1607 in the scheduling unit1602 determines whether or not to cause each mobile station apparatus102 to report the channel state information, and which DLCC the channelstate information is supposed to be reported for. The uplinktransmission resource information control unit 1608 determines an uplinktransmission resource to be assigned to each mobile station apparatus102, and store the determined uplink transmission resource.

Here, when determining an uplink transmission resource to be assigned toeach mobile station apparatus 102, an effect such as that described inthe third embodiment can be obtained by determining which ULCC theuplink transmission resource is supposed to be assigned for, based onwhether or not to cause each mobile station apparatus 102 determined bythe uplink control information control unit 1607 to report the channelstate information, and based on which DLCC the channel state informationis supposed to be reported for.

The downlink control channel control unit 1609 generates downlinkcontrol information to be notified to the mobile station apparatus 102,and determines a downlink transmission resource for transmitting aphysical downlink control channel to which the generated downlinkcontrol information is supposed to be mapped.

Here, when determining an uplink transmission resource to be notified toeach mobile station apparatus 102, an effect such as that described inthe first, the fourth, or the fifth embodiment can be obtained bygenerating downlink control information explicitly or implicitlyspecifying which DLCC the channel state information is supposed to bereported for, based on whether or not to cause each mobile stationapparatus 102 determined by the uplink control information control unit1607 to report the channel state information, and based on which DLCCthe channel state information is supposed to be reported for.

In addition, when determining a downlink transmission resource fortransmitting a physical downlink control channel to which the generateddownlink control information is supposed to be mapped, an effect such asthat described in the second or the fourth embodiment can be obtained bydetermining which DLCC the transmission resource is supposed to be usedfor, based on whether or not to cause each mobile station apparatus 102determined by the uplink control information control unit 1607 to reportthe channel state information, and based on which DLCC the channel stateinformation is supposed to be reported for.

The transmitting unit 1603 generates and transmits a downlinktransmission signal. The mapping unit 1610 in the transmitting unit 1603maps the downlink control information generated by the scheduling unit1602 to a transmission resource in the physical downlink control channeldetermined by the scheduling unit 1602, and maps the downlink data andthe downlink reference signal to a predetermined transmission resource.The radio transmitting unit 1611 converts a digital signal including themapped downlink control information into an analog signal, andup-converts it into a radio frequency band to generate a radiotransmission signal, and transmits it via the antenna unit 1605.

The receiving unit 1604 receives the uplink reception signal, andextracts uplink data. The radio receiving unit 1612 in receiving unit1604 down-converts the reception signal which has been received via theantenna unit 1605, and converts analog signals into digital signals. Thedemapping unit 1613 demaps the reception data in the uplink transmissionresource determined by the scheduling unit 1602. Here, the demappingunit 1613 extracts channel state information from a signal allocated inthe uplink transmission resource stored in the uplink transmissionresource information control unit 1608. The demodulation unit 1614performs a demodulation process corresponding to the process in amodulation unit 1714 in the mobile station apparatus 102. The decodingunit 1615 performs an error correction decoding process corresponding tothe process in a coding unit 1713 in the mobile station apparatus 102.

FIG. 17 illustrates an exemplary block configuration of the mobilestation apparatus 102 according to the present embodiment. The mobilestation apparatus 102 has a higher layer 1701, a scheduling informationmanagement unit 1702, a receiving unit (downlink receiving unit, mobilestation receiving unit) 1703, a transmitting unit (uplink transmittingunit, mobile station transmitting unit) 1704, and an antenna unit(mobile station antenna unit) 1705. The higher layer 1701 has a CCmanagement unit 1706. The scheduling information management unit 1702has a downlink control channel management unit 1710, an uplink controlinformation unit 1711, and an uplink transmission resource informationmanagement region 1712. The receiving unit 1703 has a radio receivingunit (downlink radio receiving unit) 1707, a demapping unit (downlinkdemapping unit) 1708, and a reference signal measurement unit 1709. Thetransmitting unit 1704 has a coding unit 1713, a modulation unit 1714, amapping unit (uplink mapping unit) 1715, and a radio transmitting unit(an uplink radio transmitting unit) 1716.

The CC management unit 1706 in the higher layer 1701 performs managementof the DLCC and the ULCC supported by the base station apparatus 101,and management of the DLCC and the ULCC used for communication with themobile station apparatus 102. The information set in CC management unit1706 by the CC control unit 1606 via signaling in the higher layer 1701.

The scheduling information management unit 1702 controls searching(monitoring) of downlink control information notified from the basestation apparatus 101, based on the information acquired from the higherlayer 1701, and decodes the reception data acquired from search space.In addition, upon detecting downlink control information addressed toits own apparatus from the decoded reception data, the schedulinginformation management unit 1702 extracts and stores an uplinktransmission resource addressed to its own apparatus from the downlinkcontrol information. Furthermore, when reporting the channel stateinformation, the scheduling information management unit 1702 determineswhich DLCC the channel state information is supposed to be generated(reported) for, and, if necessary, instructs the demapping unit 1708 toextract a reference signal allocated in the DLCC for which the channelstate information is supposed to be generated (reported) for.

The downlink control channel management unit 1710 in the schedulinginformation management unit 1702 sets (calculates) a DLCC and/or asearch space in which a physical downlink control channel is supposed tobe searched. In addition, using a CRC and/or an RNTI added to thedownlink control information in the DLCC and/or the search space whichhas been set, the downlink control channel management unit 1710determines whether the downlink control information is addressed to itsown apparatus. Furthermore, the downlink control channel management unit1710 determines the type or the like of the downlink control informationformat, and determines the usage of the downlink control information.

Here, when downlink control information addressed to its own apparatusis detected and reporting of channel state information is instructed, aneffect similar to that described in the second embodiment can beobtained by determining which DLCC the channel state information issupposed to be generated (reported) for, based on the DLCC and/or thesearch space set by the downlink control channel management unit 1710.

In addition, when downlink control information addressed to its ownapparatus is detected and reporting of channel state information isinstructed, an effect similar to that described in the first, thefourth, or the fifth embodiment can be obtained by determining whichDLCC the channel state information is supposed to be generated(reported) for, based on the bit sequence indicated in the bit field ofthe downlink control information.

In addition, when downlink control information addressed to its ownapparatus is detected and reporting of channel state information isinstructed, an effect similar to that described in the third or thefourth embodiment can be obtained by determining generation (reporting)of channel state information for the DLCC corresponding to the ULCCindicated in the bit field of the downlink control information.

When instructed to report the channel state information by downlinkcontrol information addressed to its own apparatus, the uplink controlinformation unit 1711 generates uplink control information including thechannel state information, based on a the measurement result output fromthe reference signal measurement unit 1709.

If the downlink control information is addressed to its own apparatus,the uplink transmission resource information management unit 1712extracts and stores an uplink transmission resource (ULCC, ifnecessary), using the format of the downlink control information and thescheduling information included in the downlink control information.Here the ULCC to be extracted may be explicitly specified by thedownlink control information, or may be preliminarily set by signalingor the like in the higher layer 1701.

The receiving unit 1703 receives the downlink reception signal andextracts the downlink control information, the reference signalmeasurement result, and the uplink extraction data. The radio receivingunit 1707 in the receiving unit 1703 has a function of down-convertingthe reception signal received via the antenna unit 1705 and convertinganalog signals into digital signals. The demapping unit 1708 demaps thereception data in the DLCC and/or the search space set by the schedulinginformation management unit 1702, and also demaps the reference signalof the DLCC set by the scheduling information management unit 1702. Inaddition, the demapping unit 1708 extracts downlink extraction data. Thereference signal measurement unit 1709 measures the reference signaldemapped by the demapping unit 1708.

The transmitting unit 1704 generates and transmits an uplinktransmission signal. The coding unit 1713 in the transmitting unit 1704performs an error correcting coding process on the uplink data. Themodulation unit 1714 performs digital modulation of theerror-correction-coded uplink data and generates a modulated symbolsequence. The mapping unit 1715 maps the modulated symbol sequence andthe uplink control information to the uplink transmission resourceextracted by the scheduling information management unit 1702. The radiotransmitting unit 1716 converts a digital signal including the mappedmodulated symbol to an analog signal, up-converts it into a radiofrequency band to generate a radio transmission signal, and transmits itvia the antenna unit 1705.

As has been shown in the foregoing, the base station apparatus 101 mayinstruct which component carrier the mobile station apparatus 102 issupposed to generate the channel state information for, whereby it ispossible to flexibly specify, in a system having two or more bands(e.g., component carriers) that can be configured for measuring(generating) the channel state information.

(a) In order to achieve the above-mentioned object, the presentinvention has taken the following measures. That is, a mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in that the base station apparatus notifies the mobilestation apparatus of downlink control information indicating for whichone of a plurality of downlink component carriers the channel stateinformation is supposed to be generated, and the mobile stationapparatus generates channel state information for a downlink componentcarrier, according to the downlink control information.

(b) In addition, the mobile communication system in which a base stationapparatus and a mobile station apparatus communicate with each otherusing a plurality of component carriers configured by a base stationapparatus, is characterized in that the base station apparatus allocatesdownlink control information in one of a plurality of downlink componentcarriers, and the mobile station apparatus generates channel stateinformation for a downlink component carrier, according to the downlinkcomponent carrier in which the downlink control information has beendetected.

(c) In addition, the mobile communication system in which a base stationapparatus and a mobile station apparatus communicate with each otherusing a plurality of component carriers configured by a base stationapparatus, is characterized in that the base station apparatus allocatesdownlink control information in one of a plurality of search spaces, andthe mobile station apparatus generates channel state information for adownlink component carrier, according to the search space in which thedownlink control information has been detected.

(d) In addition, the mobile communication system in which a base stationapparatus and a mobile station apparatus communicate with each otherusing a plurality of component carriers configured by a base stationapparatus, is characterized in that the base station apparatus notifiesthe mobile station apparatus of downlink control information by which anuplink transmission resource is assigned, and the mobile stationapparatus generates channel state information for a downlink componentcarrier, according to the downlink control information.

(e) In addition, the mobile communication system in which a base stationapparatus and a mobile station apparatus communicate with each otherusing a plurality of component carriers configured by a base stationapparatus, is characterized in that the base station apparatus notifiesthe mobile station apparatus of downlink control information indicatingan uplink component carrier in which the uplink transmission resourceassigned to the mobile station apparatus is supposed to be allocated,and the mobile station apparatus generates channel state information fora downlink component carrier, according to the downlink controlinformation.

(f) In addition, the mobile communication system in which a base stationapparatus and a mobile station apparatus communicate with each otherusing a plurality of component carriers configured by a base stationapparatus, is characterized in that the base station apparatus notifiesthe mobile station apparatus of downlink control information with apredetermined first field thereof set to a predetermined value, and themobile station apparatus changes the interpretation for a predeterminedsecond field, according to the predetermined value which has been set tothe predetermined first field of the downlink control information, andgenerates channel state information for a downlink component carrier.

(g) In addition, the mobile communication system in which a base stationapparatus and a mobile station apparatus communicate with each otherusing a plurality of component carriers configured by a base stationapparatus, is characterized in that the base station apparatus notifiesthe mobile station apparatus of downlink control information with apredetermined first field thereof set to a predetermined value, and themobile station apparatus changes the interpretation for a predeterminedsecond field, according to the predetermined value which has been set tothe predetermined first field of the downlink control information, andgenerates channel state information for a downlink component carrier.

(h) In addition, the base station apparatus in the mobile communicationsystem in which a base station apparatus and a mobile station apparatuscommunicate with each other using a plurality of component carriersconfigured by a base station apparatus is characterized in having anotifier which notifies the mobile station apparatus of downlink controlinformation indicating which one of a plurality of downlink componentcarriers the channel state information is supposed to be generated for.

(i) In addition, the mobile station apparatus in the mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in having a receiver which receives, from the base stationapparatus, downlink control information indicating which one of aplurality of downlink component carriers the channel state informationis supposed to be generated for, and a generator which generates channelstate information for a downlink component carrier, according to thedownlink control information.

(j) In addition, the mobile station apparatus in the mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in having a generator which generates channel stateinformation for a downlink component carrier, according to the downlinkcontrol carrier in which the downlink control information has beendetected.

(k) In addition, the mobile station apparatus in the mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in having a generator which generates channel stateinformation for a downlink component carrier, according to the searchspace in which the downlink control information has been detected.

(l) In addition, the mobile station apparatus in the mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in having a receiver which receives, from the base stationapparatus, downlink control information by which an uplink transmissionresource is assigned, and a generator which generates channel stateinformation for a downlink component carrier, according to the downlinkcontrol information.

(m) In addition, the mobile station apparatus in the mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in having a receiver which receives, from the base stationapparatus, downlink control information indicating an uplink componentcarrier in which the uplink transmission resource assigned by the basestation apparatus is supposed to be allocated, and a generator whichgenerates channel state information for a downlink component carrier,according to the downlink control information.

(n) In addition, the mobile station apparatus in the mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in having a receiver which receives, from the base stationapparatus, downlink control information with a predetermined first fieldthereof set to a predetermined value, and a unit of changing theinterpretation for a predetermined second field, according to thepredetermined value which has been set to the predetermined first fieldof the downlink control information, and generating channel stateinformation for a downlink component carrier.

(o) In addition, the mobile station apparatus in the mobilecommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers configured by a base station apparatus ischaracterized in having a receiver which receives, from the base stationapparatus, downlink control information with a predetermined first fieldthereof set to a predetermined value, and a unit of changing theinterpretation for a predetermined second field, according to thepredetermined value which has been set to the predetermined first fieldof the downlink control information, and generating channel stateinformation for a plurality of downlink component carriers.

(p) In addition, a communication method of an embodiment of the presentinvention is a communication method of a base station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in notifying the mobile station apparatus of downlinkcontrol information indicating which one of a plurality of downlinkcomponent carriers the channel state information is supposed to begenerated for.

(q) In addition, a communication method of an embodiment of the presentinvention is a communication method of a mobile station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in receiving, from the base station apparatus, downlinkcontrol information indicating which one of a plurality of downlinkcomponent carriers the channel state information is supposed to begenerated for, and generating channel state information for a downlinkcomponent carrier, according to the downlink control information.

(r) In addition, a communication method of an embodiment of the presentinvention is a communication method of a mobile station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in generating channel state information for a downlinkcomponent carrier, according to the downlink control carrier in whichthe downlink control information has been detected.

(s) In addition, a communication method of an embodiment of the presentinvention is a communication method of a mobile station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in generating channel state information for a downlinkcomponent carrier, according to the search space in which the downlinkcontrol information has been detected.

(t) In addition, a communication method of an embodiment of the presentinvention is a communication method of a mobile station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in receiving, from the base station apparatus, downlinkcontrol information by which an uplink transmission resource isassigned, and generating channel state information for a downlinkcomponent carrier, according to the downlink control information.

(u) In addition, a communication method of an embodiment of the presentinvention is a communication method of a mobile station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in receiving, from the base station apparatus, downlinkcontrol information indicating an uplink component carrier in which theuplink transmission resource assigned by the base station apparatus issupposed to be allocated, and generating channel state information for adownlink component carrier, according to the downlink controlinformation.

(v) In addition, a communication method of an embodiment of the presentinvention is a communication method of a mobile station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in receiving, from the base station apparatus, downlinkcontrol information with a predetermined first field thereof set to apredetermined value, changing the interpretation for a predeterminedsecond field, according to the predetermined value which has been set tothe predetermined first field of the downlink control information, andgenerating channel state information for a downlink component carrier.

(w) In addition, a communication method of an embodiment of the presentinvention is a communication method of a mobile station apparatus in amobile communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers configured by a base station apparatus,characterized in receiving, from the base station apparatus, downlinkcontrol information with a predetermined first field thereof set to apredetermined value, changing the interpretation for a predeterminedsecond field, according to the predetermined value which has been set tothe predetermined first field of the downlink control information, andgenerating channel state information for a downlink component carrier.

The program which operates on the base station apparatus 101 and themobile station apparatus 102 according to the present invention may be aprogram which controls the CPU or the like to implement the functions ofthe above-mentioned embodiments according to the present invention (aprogram which causes the computer to function). The information handledin such devices may be temporarily accumulated in a RAM at the time ofprocessing, subsequently stored in a variety of ROMs or HDDs, and read,modified, or written by the CPU as necessary. The recording media forstoring the program may be any of semiconductor media (e.g., ROM,nonvolatile memory card, etc.), optical recording media (e.g., DVD, MO,MD, CD, BD), magnetic storage media (e.g., magnetic tape, flexible disk,etc.), or the like. In addition, not only implementing the functions ofthe above-mentioned embodiments by executing the loaded program, butalso the functions of the present invention may be implemented, based oninstructions of the program, by cooperative processing with theoperating system or other application programs.

For distribution in the market, the program may be distributed in amanner stored in a portable recording medium, or transferred to a servercomputer connected via a network such as the Internet. In this case, thestorage device of the server computer is also included in the presentinvention.

In addition, a part or all of the base station apparatus 101 and themobile station apparatus 102 in the above-mentioned embodiment may beimplemented as an LSI, which is typically an integrated circuit. Eachfunction block of the base station apparatus 101 and the mobile stationapparatus 102 may be individually fabricated as a chip, or a part of allof may be integrated and fabricated as a chip. In addition, thetechnique of fabricating an integrated circuit, without being limited toan LSI, may be realized by a dedicated circuit or a general-purposeprocessor. In addition, if a technique of fabricating integratedcircuits replacing the LSI appears owing to the progress ofsemiconductor technology, an integrated circuit according to thetechnology may be used.

Although embodiments of the invention have been described in detailabove referring to the drawings, specific configurations are not limitedto the embodiments, and designs modified in a range not deviating fromthe scope of the invention are also included therein. The presentinvention can be preferably used for a radio base station apparatus, aradio mobile station apparatus 102, a radio communication system, and aradio communication method.

DESCRIPTION OF SYMBOLS

-   -   101 base station apparatus    -   102 mobile station apparatus    -   103 downlink control information    -   104 uplink transmission signal    -   1601 higher layer    -   1602 scheduling unit    -   1603 transmitting unit    -   1604 receiving unit    -   1605 antenna unit    -   1606 CC control unit    -   1607 uplink control information control unit    -   1608 uplink transmission resource information control unit    -   1609 downlink control channel control unit    -   1610 mapping unit    -   1611 radio transmitting unit    -   1612 radio receiving unit    -   1613 demapping unit    -   1614 demodulation unit    -   1615 decoding unit    -   1701 higher layer    -   1702 scheduling information management unit    -   1703 receiving unit    -   1704 transmitting unit    -   1705 antenna unit    -   1706 CC management unit    -   1707 radio receiving unit    -   1708 demapping unit    -   1709 reference signal measurement unit    -   1710 downlink control channel management district    -   1711 uplink control information generation unit    -   1712 uplink transmission resource information management unit    -   1713 coding unit    -   1714 modulation unit    -   1715 mapping unit    -   1716 radio transmitting unit    -   2001 base station apparatus    -   2002 mobile station apparatus    -   2003 downlink control information    -   2004 uplink transmission signal

The invention claimed is:
 1. A mobile station apparatus which isconfigured to communicate with a base station apparatus, the mobilestation apparatus comprising: a transceiver configured to receive on aplurality of downlink component carriers, wherein the transceiver isconfigured to receive, from the base station apparatus, a radio resourcecontrol message including first information, the first information beingused to indicate whether a carrier indicator field is present or not insecond information, and the transceiver is configured to receive on aphysical downlink control channel, from the base station apparatus, thesecond information including information for requesting a transmissionof channel state information, the second information being used forscheduling of a physical uplink shared channel in an uplink componentcarrier; and the transceiver is configured to transmit on the physicaluplink shared channel in the uplink component carrier, channel stateinformation of a first downlink component carrier of the plurality ofdownlink component carriers, wherein the transmission of the channelstate information on the physical uplink shared channel in the uplinkcomponent carrier is scheduled by using the second information that isreceived on the physical downlink control channel in the first downlinkcomponent carrier in a case that the carrier indicator field is notpresent in the second information, wherein for the second informationthat is mapped onto a first search space different from a second searchspace given by C-RNTI (Cell-Radio Network Temporal Identifier), a sizeof the information for requesting a transmission of channel stateinformation is 1 bit.
 2. The mobile station apparatus according to claim1, wherein the first downlink component carrier is indicated by the basestation apparatus.
 3. A communication method of a mobile stationapparatus which is configured to communicate with a base stationapparatus, the communication method comprising: receiving on a pluralityof downlink component carriers; receiving, from the base stationapparatus, a radio resource control message including first information,the first information being used to indicate whether a carrier indicatorfield is present or not in second information; receiving on a physicaldownlink control channel, from the base station apparatus, the secondinformation including information for requesting a transmission ofchannel state information, the second information being used forscheduling of a physical uplink shared channel in an uplink component;and transmitting on the physical uplink shared channel in the uplinkcomponent carrier, channel state information of a first downlinkcomponent carrier of the plurality of downlink component carriers,wherein the transmission of the channel state information on thephysical uplink shared channel in the uplink component carrier isscheduled by using the second information that is received on thephysical downlink control channel in the first downlink componentcarrier in a case that the carrier indicator field is not present in thesecond information, wherein for the second information that is mappedonto a first search space different from a second search space given byC-RNTI (Cell-Radio Network Temporal Identifier), a size of theinformation for requesting a transmission of channel state informationis 1 bit.
 4. The communication method according to claim 3, wherein thefirst downlink component carrier is indicated by the base stationapparatus.